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Virtual Journal of Nanoscale Science & Technology

No Evidence of Magnitude Clustering in an Aftershock Sequence of Nano- and Picoseismicity: Jorn Davidsen, Grzegorz Kwiatek, and Georg Dresen
One of the hallmarks of our current understanding of seismicity as highlighted by the epidemic-type-aftershock sequence model is that the magnitudes of earthquakes are independent of one another and can be considered as randomly drawn from the Gutenberg-Richter distribution. This assumption forms th ... [Phys. Rev. Lett. 108, 038501 ] published .
Chiral Quasicrystalline Order and Dodecahedral Geometry in Exceptional Families of Viruses: O. V. Konevtsova, S. B. Rochal, and V. L. Lorman
On the example of exceptional families of viruses we (i) show the existence of a completely new type of matter organization in nanoparticles, in which the regions with a chiral pentagonal quasicrystalline order of protein positions are arranged in a structure commensurate with the spherical topology ... [Phys. Rev. Lett. 108, 038102 ] published .
Competition between curls and plectonemes near the buckling transition of stretched supercoiled DNA: John F. Marko and Sebastien Neukirch
Recent single-molecule experiments have observed that formation of a plectonemically supercoiled region in a stretched, twisted DNA proceeds via abrupt formation of a small plectonemic bubble. A detailed mesoscopic model is presented for the formation of plectonemic domains, including their position ... [Phys. Rev. E 85, 011908 ] published .
Carrier dynamics in InN nanorod arrays: Hyeyoung Ahn, Chih-Cheng Yu, Pyng Yu, Jau Tang, Yu-Liang Hong et al.
In this report, we investigated ultrafast carrier dynamics of vertically aligned indium nitride (InN) nanorod (NR) arrays grown by molecular-beam epitaxy on Si(111) substrates. Dominant band filling effects were observed and were attributed to a partial bleaching of absorption at the probe wavelengt ... [Opt. Express 20, 769 (2012)] published Tue Jan 24, 2012.
Enhancement of light extraction in GaN-based light-emitting diodes using rough beveled ZnO nanocone arrays: Zhengmao Yin, Xiaoyan Liu, Yongzhong Wu, Xiaopeng Hao, and Xiangang Xu
A remarkable enhancement of light extraction efficiency in GaN-based blue light-emitting diodes (LEDs) with rough beveled ZnO nanocone arrays grown on the planar indium tin oxide (ITO) layer is reported. The light output power of LEDs with rough beveled ZnO nanocone arrays was increased by about 110 ... [Opt. Express 20, 1013 (2012)] published Tue Jan 24, 2012.
Morphological instability leading to formation of porous anodic oxide films: Kurt R. Hebert, Sergiu P. Albu, Indhumati Paramasivam, and Patrik Schmuki
Electrochemical oxidation of metals, in solutions where the oxide is somewhat soluble, produces anodic oxides with highly regular arrangements of pores. Although porous aluminium and titanium oxides have found extensive use in functional nanostructures, pore initiation and self-ordering are not yet ... [Nature Mater. 11, 162 (2012)] published Thu Jan 26, 2012.
High electrochemical activity of the oxide phase in model ceriaPt and ceriaNi composite anodes: William C. Chueh, Yong Hao, WooChul Jung, and Sossina M. Haile
Fuel cells, and in particular solid-oxide fuel cells (SOFCs), enable high-efficiency conversion of chemical fuels into useful electrical energy and, as such, are expected to play a major role in a sustainable-energy future. A key step in the fuel-cell energy-conversion process is the electro-oxidati ... [Nature Mater. 11, 155 (2012)] published Thu Jan 26, 2012.
Single Shot Spatial and Temporal Coherence Properties of the SLAC Linac Coherent Light Source in the Hard X-Ray Regime: C. Gutt, P. Wochner, B. Fischer, H. Conrad, M. Castro-Colin et al.
We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence ... [Phys. Rev. Lett. 108, 024801 ] published .
Crossover between Weak Antilocalization and Weak Localization in a Magnetically Doped Topological Insulator: Minhao Liu, Jinsong Zhang, Cui-Zu Chang, Zuocheng Zhang, Xiao Feng et al.
We report transport studies on magnetically doped BiSe topological insulator ultrathin films grown by molecular beam epitaxy. The magnetotransport behavior exhibits a systematic crossover between weak antilocalization and weak localization with the change of magnetic impurity concentration, temperat ... [Phys. Rev. Lett. 108, 036805 ] published .
Physical ageing of the contact line on colloidal particles at liquid interfaces: David M. Kaz, Ryan McGorty, Madhav Mani, Michael P. Brenner, and Vinothan N. Manoharan
Youngs law predicts that a colloidal sphere in equilibrium with a liquid interface will straddle the two fluids, its height above the interface defined by an equilibrium contact angle. This has been used to explain why colloids often bind to liquid interfaces, and has been exploited in emulsificati ... [Nature Mater. 11, 138 (2012)] published Thu Jan 26, 2012.
Heterogeneous Crystal Nucleation: The Effect of Lattice Mismatch: Gyula I. Toth, Gyorgy Tegze, Tamas Pusztai, and Laszlo Granasy
A simple dynamical density functional theory is used to investigate freezing of an undercooled liquid in the presence of a crystalline substrate. We find that the adsorption of the crystalline phase on the substrate, the contact angle, and the height of the nucleation barrier are nonmonotonic functi ... [Phys. Rev. Lett. 108, 025502 ] published .
Perovskite phase transformation in 0.65Pb(MgNb)O-0.35PbTiO nanoparticles derived by sol-gel: Satyendra Singh and S. B. Krupanidhi
Fabrication of 0.65Pb(MgNb)O-0.35PbTiO (PMN-PT) nanoparticles with an average size of about 40 nm and their phase transformation behavior from pyrochlore to perovskite phase is investigated. A novel sol-gel method was used for the synthesis of air-stable and precipitate-free diol-based sol of PMN-PT ... [J. Appl. Phys. 111, 024314 (2012)] published Thu Jan 26, 2012.
Plasmonic light trapping leads to responsivity increase in colloidal quantum dot photodetectors: F. Pelayo Garcia de Arquer, Fiona J. Beck, Maria Bernechea, and Gerasimos Konstantatos
We report broadband responsivity enhancement in PbS colloidal quantum dot (CQDs) photoconductive photodetectors due to absorption increase offered by a plasmonic scattering layer of Ag metal nanoparticles. Responsivity enhancements are observed in the near infrared with a maximum 2.4-fold increase n ... [Appl. Phys. Lett. 100, 043101 (2012)] published Mon Jan 23, 2012.
Morphological control of hybrid polymer-quantum dot solar cells with electron acceptor ligands: Mathieu Boivin, Sebastien Lamarre, Jonathan Tessier, Marie-Eve Lecavalier, Ahmed Najari et al.
We integrate the electro-attractive conjugated molecule tetrafluoro-tetracyano-quinodimethane (FTCNQ) in the active layer of polymer-CdSe colloidal quantum dot (cQD) solar cells. The addition of this molecule enhances cQD dispersion inside the polymer. In tuning its concentration, we can optimize th ... [Appl. Phys. Lett. 100, 033302 (2012)] published Fri Jan 20, 2012.
Aspect-ratio-dependent phase transitions and concentration fluctuations in aqueous colloidal dispersions of charged platelike particles: Daisuke Yamaguchi, Nobuyoshi Miyamoto, Takako Fujita, Teruyuki Nakato, Satoshi Koizumi et al.
Phase transitions of aqueous colloidal dispersions of charged platelike particles of niobate nanosheets were investigated as a function of the aspect ratio (r) and particle volume concentration ([cursive phi]) by means of small-angle neutron scattering and small-angle x-ray scattering. The results e ... [Phys. Rev. E 85, 011403 ] published .
Effective Viscosity of Confined Hydrocarbons: I. M. Sivebaek, V. N. Samoilov, and B. N. J. Persson
We present molecular dynamics friction calculations for confined hydrocarbon films with molecular lengths from 20 to 1400 carbon atoms. We find that the logarithm of the effective viscosity eta for nanometer-thin films depends linearly on the logarithm of the shear rate: logeta=C-nlog gamma-dot, whe ... [Phys. Rev. Lett. 108, 036102 ] published .
Self-Sustained Localized Structures in a Boundary-Layer Flow: Yohann Duguet, Philipp Schlatter, Dan S. Henningson, and Bruno Eckhardt
When a boundary layer starts to develop spatially over a flat plate, only disturbances of sufficiently large amplitude survive and trigger turbulence subcritically. Direct numerical simulation of the Blasius boundary-layer flow is carried out to track the dynamics in the region of phase space separa ... [Phys. Rev. Lett. 108, 044501 ] published .
Reorientation dynamics of nanoconfined water: Power-law decay, hydrogen-bond jumps, and test of a two-state model: Damien Laage and Ward H. Thompson
The reorientation dynamics of water confined within nanoscale, hydrophilic silica pores are investigated using molecular dynamics simulations. The effect of surface hydrogen-bonding and electrostatic interactions are examined by comparing with both a silica pore with no charges (representing hydroph ... [J. Chem. Phys. 136, 044513 (2012)] published Wed Jan 25, 2012.
Noncollinear Fe spin structure in (Sm-Co)/Fe exchange-spring bilayers: Layer-resolved Fe Mossbauer spectroscopy and electronic structure calculations: V. M. Uzdin, A. Vega, A. Khrenov, W. Keune, V. E. Kuncser et al.
Magnetization reversal in nanoscale (Sm-Co)/Fe (hard/soft) bilayer exchange-spring magnets with in-plane uniaxial magnetic anisotropy was investigated by magnetometry, conversion-electron Mossbauer spectroscopy (CEMS) and atomistic Fe spin-structure calculations. Magnetization loops along the easy d ... [Phys. Rev. B 85, 024409 ] published .
Mechanism for recombination of radiation-induced point defects at interphase boundaries: X.-Y. Liu, B. P. Uberuaga, M. J. Demkowicz, T. C. Germann, A. Misra et al.
Interfaces play a critical role in the extraordinary resistance to irradiation damage in nanostructured materials. Atomistic simulations are performed to examine defect production and recovery at incoherent interphase boundaries with different atomic structures. The interstitials produced during cas ... [Phys. Rev. B 85, 012103 ] published .
Surface modification by subsurface pressure induced diffusion: Claus G. Zimmermann
Polycrystalline Ag, covered with a nm thin siloxane layer, was irradiated with ultraviolet light in vacuum at 500 K. Ag particles of different aspect ratios, 501000 nm in size, formed on the surface, including a small fraction of nanorods. Pressurized water vapor bubbles are created in the subsurfac ... [Appl. Phys. Lett. 100, 041908 (2012)] published Thu Jan 26, 2012.
Spark discharge formation in an inhomogeneous electric field under conditions of runaway electron generation: Tao Shao (邵涛), Victor F. Tarasenko, Cheng Zhang (章程), Mikhail I. Lomaev, Dmitrii A. Sorokin et al.
In this article we report on work where the formation of a spark in nanosecond high-voltage discharges was studied in nitrogen, nitrogen-methane mixtures, and air at increased pressures under the conditions of runaway electron generation. Voltage pulses of amplitude ~90 and ~250 kV were applied to a ... [J. Appl. Phys. 111, 023304 (2012)] published Mon Jan 23, 2012.
Mid-infrared spectroscopy of molecular ions in helium nanodroplets: Xiaohang Zhang, Nils B. Brauer, Giel Berden, Anouk M. Rijs, and Marcel Drabbels
High resolution IR spectra of aniline, styrene, and 1,1-diphenylethylene cations embedded in superfluid helium nanodroplets have been recorded in the 3001700 cm range using a free-electron laser as radiation source. Comparison of the spectra with available gas phase data reveals that the helium envi ... [J. Chem. Phys. 136, 044305 (2012)] published Tue Jan 24, 2012.
Vibrational energy relaxation of benzene dimer and trimer in the CH stretching region studied by picosecond time-resolved IR-UV pump-probe spectroscopy: Ryoji Kusaka, Yoshiya Inokuchi, and Takayuki Ebata
Vibrational energy relaxation (VER) of the Fermi polyads in the CH stretching vibration of the benzene dimer (Bz) and trimer (Bz) has been investigated by picosecond (ps) time-resolved IR-UV pump-probe spectroscopy in a supersonic beam. The vibrational bands in the 30003100 cm region were excited by ... [J. Chem. Phys. 136, 044304 (2012)] published Mon Jan 23, 2012.
Ultrafast Viscous Permeation of Organic Solvents Through Diamond-Like Carbon Nanosheets: Santanu Karan, Sadaki Samitsu, Xinsheng Peng, Keiji Kurashima, and Izumi Ichinose
Chemical, petrochemical, energy, and environment-related industries strongly require high-performance nanofiltration membranes applicable to organic solvents. To achieve high solvent permeability, filtration membranes must be as thin as possible, while retaining mechanical strength and solvent resis ... [Science 335, 444 (2012)] published Tue Jan 24, 2012.
A new experimental setup designed for the investigation of irradiation of nanosystems in the gas phase: A high intensity mass-and-energy selected cluster beam: G. Bruny, S. Eden, S. Feil, R. Fillol, K. El Farkh et al.
DIAM (Dispositif d'Irradiation d'Agregats Moleculaires) is a new experimental setup devoted to investigate processes induced by irradiation at the nanoscale. The DIAM apparatus is based on a combination of techniques including a particle beam from high-energy physics, a cluster source from molecular ... [Rev. Sci. Instrum. 83, 013305 (2012)] published Fri Jan 20, 2012.
Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level: We compare the charge transport characteristics of heavy-doped p- and n-Si-alkyl chain/Hg junctions. Based on negative differential resistance in an analogous semiconductor-inorganic insulator/metal junction we suggest that for both p- and n-type junctions, the energy difference between the Fermi le ... [Phys. Rev. B 85, 045433 ] published .
Ambipolar transition voltage spectroscopy: Analytical results and experimental agreement: Ioan Baldea
This work emphasizes that the transition voltages V for both bias polarities (V [greater, less] 0) should be used to properly determine the energy offset [eh] of the molecular orbital closest to electrodes' Fermi level and the bias asymmetry gamma in molecular junctions. Accurate analytical formulas ... [Phys. Rev. B 85, 035442 ] published .
Characterization of 1064nm nanosecond laser-induced damage on antireflection coatings grown by atomic layer deposition: Zhichao Liu, Songlin Chen, Ping Ma, Yaowei Wei, Yi Zheng et al.
Damage tests are carried out at 1064nm to measure the laser resistance of TiO/AlOand HfO/AlO antireflection coatings grown by atomic layer deposition (ALD). The damage results are determined by S-on-1 and R-on-1 tests. Interestingly, the damage performance of ALD coatings is similar to those grown b ... [Opt. Express 20, 854 (2012)] published Tue Jan 24, 2012.
Correlated nucleation and self-accommodating kinetic pathway of ferroelectric phase transformation: Jie E. Zhou, Tian-Le Cheng, and Yu U. Wang
Mechanisms of nucleation and growth of domains during ferroelectric phase transformation are investigated by using theoretical and computational approaches. It is shown that ferroelectric phase transformation exhibits some peculiar behaviors due to strong long-range dipole-dipole-like interactions i ... [J. Appl. Phys. 111, 024105 (2012)] published Wed Jan 25, 2012.
Random and Ordered Phases of Off-Lattice Rhombus Tiles: Stephen Whitelam, Isaac Tamblyn, Peter H. Beton, and Juan P. Garrahan
We study the covering of the plane by nonoverlapping rhombus tiles, a problem well studied only in the limiting case of dimer coverings of regular lattices. We go beyond this limit by allowing tiles to take any position and orientation on the plane, to be of irregular shape, and to possess different ... [Phys. Rev. Lett. 108, 035702 ] published .
Atomistic pseudopotential theory of spin relaxation in self-assembled InGaAs/GaAs quantum dots at zero magnetic field: Hai Wei, Ming Gong, Guang-Can Guo, and Lixin He
An atomistic pseudopotential calculation of the spin-flip time (T) of electrons and holes mediated by acoustic phonons in self-assembled InGaAs/GaAs quantum dots at zero magnetic field is presented. At low magnetic field, the first-order process is suppressed, and the second-order process becomes do ... [Phys. Rev. B 85, 045317 ] published .
Bragg wave coupling in self-assembled opal photonic crystals: Rajesh V. Nair and B. N. Jagatap
The optical properties of three-dimensionally-ordered self-assembled photonic crystals are studied in the Bragg wave coupling regime. Angle-resolved photonic stop gap measurements show the Bragg wave coupling extending over an angular range of 18 degrees . The new diffraction peak originating at the ... [Phys. Rev. A 85, 013829 ] published .
Reconfigurable self-assembly through chiral control of interfacial tension: Thomas Gibaud, Edward Barry, Mark J. Zakhary, Mir Henglin, Andrew Ward et al.
From determining the optical properties of simple molecular crystals to establishing the preferred handedness in highly complex vertebrates, molecular chirality profoundly influences the structural, mechanical and optical properties of both synthetic and biological matter on macroscopic length scal ... [Nature 481, 348 (2012)] published Fri Jan 20, 2012.
Self-assembly of uniform polyhedral silver nanocrystals into densest packings and exoticsuperlattices: Joel Henzie, Michael Grnwald, Asaph Widmer-Cooper, Phillip L. Geissler, and Peidong Yang
Understanding how polyhedra pack into extended arrangements is integral to the design and discovery of crystalline materials at all length scales. Much progress has been made in enumerating and characterizing the packing of polyhedral shapes, and the self-assembly of polyhedral nanocrystals into or ... [Nature Mater. 11, 131 (2012)] published Thu Jan 26, 2012.
Nuclear Spins of Ionized Phosphorus Donors in Silicon: Lukas Dreher, Felix Hoehne, Martin Stutzmann, and Martin S. Brandt
We demonstrate the coherent control and electrical readout of ionized phosphorus donor nuclear spins in Si. By combining time-programed optical excitation with coherent electron spin manipulation, we selectively ionize the donors depending on their nuclear spin state, exploiting a spin-dependent rec ... [Phys. Rev. Lett. 108, 027602 ] published .
Configuration interaction calculations of the controlled phase gate in double quantum dot qubits: Erik Nielsen, Richard P. Muller, and Malcolm S. Carroll
We consider qubit coupling resulting from the capacitive coupling between two double quantum dot (DQD) singlet-triplet qubits. Calculations of the coupling when the two DQDs are detuned symmetrically or asymmetrically are performed using a full configuration interaction (CI). The full CI reveals beh ... [Phys. Rev. B 85, 035319 ] published .
Relaxation and readout visibility of a singlet-triplet qubit in an Overhauser field gradient: C. Barthel, J. Medford, H. Bluhm, A. Yacoby, C. M. Marcus et al.
Using single-shot charge detection in a GaAs double quantum dot, we investigate spin relaxation time (T) and readout visibility of a two-electron singlet-triplet qubit following single-electron dynamic nuclear polarization (DNP). For magnetic fields up to 2 T, the DNP cycle is in all cases found to ... [Phys. Rev. B 85, 035306 ] published .
Majorana zero modes in a quantum Ising chain with longer-ranged interactions: Yuezhen Niu, Suk Bum Chung, Chen-Hsuan Hsu, Ipsita Mandal, S. Raghu et al.
A one-dimensional Ising model in a transverse field can be mapped onto a system of spinless fermions with p-wave superconductivity. In the weak-coupling BCS regime, it exhibits a zero-energy Majorana mode at each end of the chain. Here, we consider a variation of the model, which represents a superc ... [Phys. Rev. B 85, 035110 ] published .
Generation of maximally-polarization-entangled photons on a chip: Sergei V. Zhukovsky, Lukas G. Helt, Dongpeng Kang, Payam Abolghasem, Amr S. Helmy et al.
We propose a method of generating maximally-polarization-entangled states by type-II spontaneous parametric down-conversion in Bragg reflection waveguides. Analytic expressions for the group velocities of down-converted modes are used to engineer zero group-velocity mismatch at the operating point, ... [Phys. Rev. A 85, 013838 ] published .
Multiple-spin coherence transfer in linear Ising spin chains and beyond: Numerically optimized pulses and experiments: Manoj Nimbalkar, Robert Zeier, Jorge L. Neves, S. Begam Elavarasi, Haidong Yuan et al.
We study multiple-spin coherence transfers in linear Ising spin chains with nearest-neighbor couplings. These constitute a model for efficient information transfers in future quantum computing devices and for many multidimensional experiments for the assignment of complex spectra in nuclear magnetic ... [Phys. Rev. A 85, 012325 ] published .
Entanglement in stationary nonequilibrium states at high energies: Marko ZnidariC
In recent years it has been found that quantum systems can posses entanglement in equilibrium thermal states provided temperature is low enough. In the present work we explore a possibility of having entanglement in nonequilibrium stationary states. We show analytically that, in a simple one-dimensi ... [Phys. Rev. A 85, 012324 ] published .
Spin chains for robust state transfer: Modified boundary couplings versus completely engineered chains: Analia Zwick, Gonzalo A. Alvarez, Joachim Stolze, and Omar Osenda
Quantum state transfer in the presence of static disorder and noise is one of the main challenges in building quantum computers. We compare the quantum state transfer properties for two classes of qubit chains under the influence of static disorder. In fully engineered chains all nearest-neighbor co ... [Phys. Rev. A 85, 012318 ] published .
Decoherence control: Universal protection of two-qubit states and two-qubit gates using continuous driving fields: Adam Zaman Chaudhry and Jiangbin Gong
A field configuration utilizing local static fields and a few continuous-wave driving fields is constructed to achieve universal (but low-order) protection of two-qubit states. That is, two-qubit states can be protected against arbitrary system-environment coupling with control fields if their frequ ... [Phys. Rev. A 85, 012315 ] published .
Maximally entangled gapped ground state of lattice fermions: David L. Feder
Entanglement between the constituents of a quantum system is an essential resource in the implementation of many quantum processes and algorithms. Indeed, universal quantum computation is possible by measuring individual qubits that constitute highly entangled cluster states. In this work, it is sho ... [Phys. Rev. A 85, 012312 ] published .
Topologically protected measurement-based quantum computation on the thermal state of a nearest-neighbor two-body Hamiltonian with spin-3/2 particles: Keisuke Fujii and Tomoyuki Morimae
Recently, Li et al. [Phys. Rev. Lett. 107, 060501 (2011)] have demonstrated that topologically protected measurement-based quantum computation can be implemented on the thermal state of a nearest-neighbor two-body Hamiltonian with spin-2 and spin-3/2 particles provided that the temperature is smalle ... [Phys. Rev. A 85, 010304 ] published .
Dipole Coupling of a Double Quantum Dot to a Microwave Resonator: T. Frey, P. J. Leek, M. Beck, A. Blais, T. Ihn et al.
We demonstrate the realization of a hybrid solid-state quantum device, in which a semiconductor double quantum dot is dipole coupled to the microwave field of a superconducting coplanar waveguide resonator. The double dot charge stability diagram extracted from measurements of the amplitude and phas ... [Phys. Rev. Lett. 108, 046807 ] published .
Magnetic-Field Probing of an SU(4) Kondo Resonance in a Single-Atom Transistor: G. C. Tettamanzi, J. Verduijn, G. P. Lansbergen, M. Blaauboer, M. J. Calderon et al.
Semiconductor devices have been scaled to the point that transport can be dominated by only a single dopant atom. As a result, in a Si fin-type field effect transistor Kondo physics can govern transport when one electron is bound to the single dopant. Orbital (valley) degrees of freedom, apart from ... [Phys. Rev. Lett. 108, 046803 ] published .
Two-Photon Quantum Interference from Separate Nitrogen Vacancy Centers in Diamond: Hannes Bernien, Lilian Childress, Lucio Robledo, Matthew Markham, Daniel Twitchen et al.
We report on the observation of quantum interference of the emission from two separate nitrogen vacancy (NV) centers in diamond. Taking advantage of optically induced spin polarization in combination with polarization filtering, we isolate a single transition within the zero-phonon line of the nonre ... [Phys. Rev. Lett. 108, 043604 ] published .
Benchmarking a Quantum Teleportation Protocol in Superconducting Circuits Using Tomography and an Entanglement Witness: M. Baur, A. Fedorov, L. Steffen, S. Filipp, M. P. da Silva et al.
Teleportation of a quantum state may be used for distributing entanglement between distant qubits in quantum communication and for quantum computation. Here we demonstrate the implementation of a teleportation protocol, up to the single-shot measurement step, with superconducting qubits coupled to a ... [Phys. Rev. Lett. 108, 040502 ] published .
Majorana Modes in Time-Reversal Invariant s-Wave Topological Superconductors: Shusa Deng, Lorenza Viola, and Gerardo Ortiz
We present a time-reversal invariant s-wave superconductor supporting Majorana edge modes. The multiband character of the model together with spin-orbit coupling are key to realizing such a topological superconductor. We characterize the topological phase diagram by using a partial Chern number sum, ... [Phys. Rev. Lett. 108, 036803 ] published .
Entanglement of Three-Qubit Greenberger-Horne-ZeilingerSymmetric States: Christopher Eltschka and Jens Siewert
The first characterization of mixed-state entanglement was achieved for two-qubit states in Werner's seminal work [Phys. Rev. A 40, 4277 (1989)]. A physically important extension concerns mixtures of a pure entangled state [such as the Greenberger-Horne-Zeilinger (GHZ) state] and the unpolarized sta ... [Phys. Rev. Lett. 108, 020502 ] published .
Measuring which-path information with coupled electronic Mach-Zehnder interferometers: J. Dressel, Y. Choi, and A. N. Jordan
We theoretically investigate a generalized which-path measurement on an electronic Mach-Zehnder Interferometer (MZI) implemented via Coulomb coupling to a second electronic MZI acting as a detector. The use of contextual values, or generalized eigenvalues, enables the precise construction of which-p ... [Phys. Rev. B 85, 045320 ] published .
Edge-mode combinations in the entanglement spectra of non-Abelian fractional quantum Hall states on the torus: Zhao Liu, Emil J. Bergholtz, Heng Fan, and Andreas M. Lauchli
We present a detailed analysis of bipartite entanglement in the non-Abelian Moore-Read fractional quantum Hall state of bosons and fermions on the torus. In particular, we show that the entanglement spectra can be decomposed into intricate combinations of different sectors of the conformal field the ... [Phys. Rev. B 85, 045119 ] published .
Quantum state transfer between hybrid qubits in a circuit QED: Zhi-Bo Feng
In this Brief Report, we propose a theoretical scheme to transfer quantum states between superconducting charge qubits and semiconductor spin qubits in a circuit QED device. Under dispersive conditions, resonator-assisted state transfer between qubits can be performed controllably only by addressing ... [Phys. Rev. A 85, 014302 ] published .
Fracturing graphene by chlorination: A theoretical viewpoint: M. Ijas, P. Havu, and A. Harju
Motivated by a recent photochlorination experiment [B. Li et al., ACS Nano 5, 5957 (2011)], we study theoretically the interaction of chlorine with graphene. In previous theoretical studies, covalent binding between chlorine and carbon atoms has been elusive upon adsorption to the graphene basal pla ... [Phys. Rev. B 85, 035440 ] published .
Dirac donor states controlled by magnetic field in gapless and gapped graphene: Jia-Lin Zhu, Songyang Sun, and Ning Yang
In this paper, the exact solutions of Dirac electronic states of graphene in Coulomb and magnetic fields are acquired. The Coulomb field not only causes the splitting of Landau levels in gapless graphene but also leads to the variation of the energy level ordering in gapped graphene. The dependence ... [Phys. Rev. B 85, 035429 ] published .
Observation of Landau-level-like quantization at 77 K along a strained-induced graphene ridge: Hui Yan, Yi Sun, Lin He, Jia-Cai Nie, and Moses H. W. Chan
Recent studies show that the electronic structures of graphene can be modified by strain, and it was predicted that strain in graphene can induce peaks in the local density of states (LDOS), mimicking Landau levels (LLs) generated in the presence of a large magnetic field. Here we report the scannin ... [Phys. Rev. B 85, 035422 ] published .
Influence of charge transfer doping on the morphologies of C islands on hydrogenated diamond C(100)-(2 x 1): Markus Nimmrich, Markus Kittelmann, Philipp Rahe, Wolfgang Harneit, Andrew J. Mayne et al.
The adsorption and island formation of C fullerenes on the hydrogenated C(100)-(2 x 1):H diamond surface is studied using high-resolution noncontact atomic force microscopy in ultrahigh vacuum. At room temperature, C fullerene molecules assemble into monolayer islands, exhibiting a hexagonally close ... [Phys. Rev. B 85, 035420 ] published .
Superfluidity of dipole excitons in the presence of band gaps in two-layer graphene: Oleg L. Berman, Roman Ya. Kezerashvili, and Klaus Ziegler
We propose to observe superfluidity of quasi-two-dimensional dipole excitons in double-layer graphene in the presence of band gaps. The energy spectrum of the collective excitations, the sound spectrum, and the effective exciton mass are functions of the energy gaps, density, and interlayer separati ... [Phys. Rev. B 85, 035418 ] published .
Trions in semiconducting single-walled carbon nanotubes: Kouta Watanabe and Kenichi Asano
We study trions (charged excitons), a complex of an electron-hole pair and an additional electron or hole, in semiconducting single-walled carbon nanotubes (s-SWCNT), by means of the exact diagonalization of the realistic Hamiltonian based on the kp scheme and on the screened Hartree-Fock approximat ... [Phys. Rev. B 85, 035416 ] published .
Nonlinear strain effects in double-resonance Raman bands of graphite, graphene, and related materials: Elena del Corro, Mercedes Taravillo, and Valentin G. Baonza
We analyze the influence of biaxial strain on the double-resonance (D and 2D) Raman bands of graphite-related materials. A substantial nonlinear dependence of these bands with the strain is observed, evidencing a quite different effect on the electronic structure around the K and Gamma points of the ... [Phys. Rev. B 85, 033407 ] published .
Layer-resolved conductivities in multilayer graphene: Takeo Wakutsu, Masaaki Nakamura, and Balazs Dora
We study interlayer transport of multilayer graphenes in a magnetic field with various stacking structures (AB, ABC, and AA types) by calculating the Hall and longitudinal conductivities as functions of the Fermi energy. Their behavior depends strongly on the stacking structures and selection of the ... [Phys. Rev. B 85, 033403 ] published .
Graphene production by laser shot on graphene oxide: An ab initio prediction: Hong Zhang and Yoshiyuki Miyamoto
By performing the first-principles simulation of electron-ion dynamics based on the time-dependent density-functional theory, we propose a way to produce graphene from graphene oxides by means of the laser-induced reduction without using chemical species. Epoxy and hydroxyl groups on graphene sheets ... [Phys. Rev. B 85, 033402 ] published .
Interband effects of magnetic field on Hall conductivity in the multilayered massless Dirac fermion system alpha-(BEDT-TTF)I: Naoya Tajima, Reizo Kato, Shigeharu Sugawara, Yutaka Nishio, and Koji Kajita
We have discovered a two-dimensional zero-gap material with a layered structure in the organic conductor alpha-(BEDT-TTF)I under high hydrostatic pressure. In contrast to graphene, the electron-hole symmetry is not good except at the vicinity of the Dirac points. Thus, the temperature dependence of ... [Phys. Rev. B 85, 033401 ] published .
Atomic-scale transport in epitaxial graphene: Shuai-Hua Ji, J. B. Hannon, R. M. Tromp, V. Perebeinos, J. Tersoff et al.
The high carrier mobility of graphene is key to its applications,and understanding the factors that limit mobility is essential for future devices. Yet, despite significant progress, mobilities in excess of the 210cmVs demonstrated in free-standing graphene films have not been duplicated in convent ... [Nature Mater. 11, 114 (2012)] published Thu Jan 26, 2012.
Structural and electronic properties of single-wall carbon nanotubes with various nitrogen content: V. G. Boutko, A. A. Gusev, T. N. Shevtsova, and Yu. G. Pashkevich
The band structure of a carbon-nitrogen nanotube of zigzag type (8, 0) with nitrogen atom concentrations of 6.25%, 12.5%, and 25% and armchair (5, 5) carbon-nitrogen nanotube with nitrogen atom concentrations of 10% and 20% is calculated within the density functional theory approach. The calculation ... [Low Temp. Phys. 37, 1021 (2012)] published Wed Jan 25, 2012.
Electrical properties of C and Si codoped GaAs layers: Jiro Nishinaga and Yoshiji Horikoshi
C uniformly doped GaAs and C, Si codoped GaAs layers are grown by a migration enhanced epitaxy method. C doped GaAs layers show a single and sharp diffraction peak in x-ray diffraction and only an LO phonon peak is confirmed, indicating that the crystalline quality is fairly good. All of the C doped ... [J. Vac. Sci. Technol. B 30, 02B116 (2012)] published Tue Jan 24, 2012.
Evidence of ferroelectricity and phase transition in pressed diphenylalanine peptide nanotubes: Igor Bdikin, Vladimir Bystrov, Svitlana Kopyl, Rui P. G. Lopes, Ivonne Delgadillo et al.
Self-assembled peptide nanotubes (PNT) are unique nanoscale objects having a great potential for a multitude of applications. Strong piezoactivity and polar properties in aromatic dipeptides were recently observed in stand-alone nanotubes using piezoresponse force microscopy and 2 harmonic generatio ... [Appl. Phys. Lett. 100, 043702 (2012)] published Tue Jan 24, 2012.
Ceasing of voltage switching amongst graphitic shells in multiwalled carbon nanotubes: A route toward stability: Neha Kulshrestha, Abhishek Misra, Reeti Bajpai, Soumyendu Roy, and D. S. Misra
Weakly interacting graphitic shells of different resistivities within multiwalled carbon nanotubes (MWNTs) cause instability in current and thus limit their reliability for electronic device applications. We here demonstrate voltage switching amongst graphitic shells of MWNTs by applying current swe ... [Appl. Phys. Lett. 100, 043505 (2012)] published Tue Jan 24, 2012.
High magnetic field annealing effect on visible photoluminescence enhancement of TiO nanotube arrays: Mingjie Yang, Wei Liu, Jia-Lin Sun, and Jia-Lin Zhu
TiO nanotube arrays with remarkable visible photoluminescence were prepared by high magnetic field annealing in air at 450 degrees C due to the involvement of oxygen vacancies (OVs). A field with the intensities of 0, 2, 4, 6, and 8 T were applied in the annealing processing, along the directions s ... [Appl. Phys. Lett. 100, 043106 (2012)] published Wed Jan 25, 2012.
Improved electron field emission from morphologically disordered monolayer graphene: Srikrishna Pandey, Padmnabh Rai, Shashikant Patole, Fethullah Gunes, Gi-Duk Kwon et al.
Graphene was synthesized on copper foil by thermal chemical vapor deposition technique. To investigate the field electron emission property, planar graphene (PG) and morphologically disordered graphene (MDG) were fabricated on the doped silicon substrate by transfer of as-grown graphene. Incorporati ... [Appl. Phys. Lett. 100, 043104 (2012)] published Tue Jan 24, 2012.
Transforming graphite to nanoscale diamonds by a femtosecond laser pulse: R. Nuske, A. Jurgilaitis, H. Enquist, M. Harb, Y. Fang et al.
Formation of cubic diamond from graphite following irradiation by a single, intense, ultra-short laser pulse has been observed. Highly oriented pyrolytic graphite (HOPG) samples were irradiated by a 100 fs pulse with a center wavelength of 800 nm. Following laser exposure, the HOPG samples were stud ... [Appl. Phys. Lett. 100, 043102 (2012)] published Mon Jan 23, 2012.
Recoverable electrical transition in a single graphene sheet for application in nonvolatile memories: Chaoxing Wu, Fushan Li, Yongai Zhang, and Tailiang Guo
The electrical properties of a resistive-switching memory based on a single graphene sheet suspended on a patterned indium-tin-oxide electrode pair were investigated. Current-voltage measurements on the planar device showed a large ON/OFF ratio (~10) and excellent retention ability in ambient condit ... [Appl. Phys. Lett. 100, 042105 (2012)] published Wed Jan 25, 2012.
Size of the Localized Electron Emission Sites on a Closed Multiwalled Carbon Nanotube: Erwin C. Heeres, Tjerk H. Oosterkamp, and Niels de Jonge
We have measured the size of the localized electron emission sites on multiwalled carbon nanotubes (MWNTs) with caps closed by a fullerenelike structure. MWNTs were individually mounted on tungsten support tips and imaged with a field emission microscope (FEM). The magnification of the FEM was calib ... [Phys. Rev. Lett. 108, 036804 ] published .
Synthesis of monolithic graphenegraphite integrated electronics: Jang-Ung Park, SungWoo Nam, Mi-Sun Lee, and Charles M. Lieber
Encoding electronic functionality into nanoscale elements during chemical synthesis has been extensively explored over the past decade as the key to developing integrated nanosystems with functions defined by synthesis. Graphene has been recently explored as a two-dimensional nanoscale material, an ... [Nature Mater. 11, 120 (2012)] published Thu Jan 26, 2012.
Measurement of Quantum Noise in a Carbon Nanotube Quantum Dot in the Kondo Regime: J. Basset, A. Yu. Kasumov, C. P. Moca, G. Zarand, P. Simon et al.
The current emission noise of a carbon nanotube quantum dot in the Kondo regime is measured at frequencies nu of the order or higher than the frequency associated with the Kondo effect kT/h, with T the Kondo temperature. The carbon nanotube is coupled via an on-chip resonant circuit to a quantum noi ... [Phys. Rev. Lett. 108, 046802 ] published .
Effect of van der Waals interaction on energetics and transport properties of a single anthracene molecule adsorbed or confined inside a carbon nanotube: L. Debbichi, Y. J. Dappe, and M. Alouani
The energetics and transport properties of a single aromatic molecule (CH) in interaction with a metallic single-walled carbon nanotube (SWCNT) have been studied using state-of-the-art density functional calculations. In both adsorption and encapsulation configurations, we show that the fundamental ... [Phys. Rev. B 85, 045437 ] published .
Native defects in hybrid C/BN nanostructures by density functional theory calculations: J. M. Pruneda
First-principles calculations of substitutional defects and vacancies are performed for zigzag-edged hybrid C/BN nanosheets and nanotubes which recently have been proposed to exhibit half-metallic properties. The formation energies show that defects form preferentially at the interfaces between grap ... [Phys. Rev. B 85, 045422 ] published .
Theory of thermal transport in multilayer hexagonal boron nitride and nanotubes: L. Lindsay and D. A. Broido
We present a theory for the lattice thermal conductivity kappa of single-walled boron nitride nanotubes (BNNTs) and multilayer hexagonal boron nitride (MLBN), which is based on an exact numerical solution of the phonon Boltzmann equation. Coupling between layers in MLBN and nanotube curvature in BNN ... [Phys. Rev. B 85, 035436 ] published .
Raman spectroscopy of substrate-induced compression and substrate doping in thermally cycled graphene: Chun-Chung Chen, Wenzhong Bao, Chia-Chi Chang, Zeng Zhao, Chun Ning Lau et al.
By thermally cycling single layer graphene in air, we observe irreversible upshifts of the Raman G and 2D bands of 24 and 23 cm, respectively. These upshifts are attributed to an in-plane compression of the graphene induced by the mismatch of thermal expansion coefficients between the graphene and t ... [Phys. Rev. B 85, 035431 ] published .
Side-dependent electron escape from graphene- and graphane-like SiC layers: Paola Gori, Olivia Pulci, Margherita Marsili, and Friedhelm Bechstedt
The structural and electronic properties of SiC-based two-dimensional (2D) crystals are studied by means of density functional theory and many-body perturbation theory. Such properties cannot simply be interpolated between graphene and silicene. The replacement of half of the C atoms by Si atoms ope ... [Appl. Phys. Lett. 100, 043110 (2012)] published Thu Jan 26, 2012.
Anomalous electron transport in back-gated field-effect transistors with TiTe semimetal thin-film channels: J. Khan, C. M. Nolen, D. Teweldebrhan, D. Wickramaratne, R. K. Lake et al.
The authors report on graphene-like mechanical exfoliation of thin films of titanium ditelluride and investigation of their electronic properties. The exfoliated crystalline TiTe films were used as the channel layers in the back-gated field-effect transistors fabricated with Ti/Al/Au metal contacts ... [Appl. Phys. Lett. 100, 043109 (2012)] published Thu Jan 26, 2012.
Effective energy gap of the double-walled carbon nanotubes with field effect transistors ambipolar characteristics: Takahiro Morimoto, Akihiro Kuno, Shota Yajima, Koji Ishibashi, Koji Tsuchiya et al.
We have investigated the transport property of the double-walled carbon nanotubes (DWCNT)-field effect transistor (FET) devices with HfO insulating layers at room temperature and 4.2 K. These devices show the ambipolar FET characteristics after deposition of HfO insulating layer. The off-regions of ... [Appl. Phys. Lett. 100, 043107 (2012)] published Thu Jan 26, 2012.
Enhancing interwall load transfer by vacancy defects in carbon nanotubes: David Santo Pietro, Chun Tang, and Changfeng Chen
Structural defects usually reduce the load carrying capacity of materials. Here, we show by molecular dynamics simulations an anomalous vacancy-defect-induced enhancement of interwall load transfer in annealed carbon nanotubes (CNTs). The large increase of load transfer mainly stems from the hybrid ... [Appl. Phys. Lett. 100, 033118 (2012)] published Fri Jan 20, 2012.
Wave-Function Mapping of Graphene Quantum Dots with Soft Confinement: D. Subramaniam, F. Libisch, Y. Li, C. Pauly, V. Geringer et al.
Using low-temperature scanning tunneling spectroscopy, we map the local density of states of graphene quantum dots supported on Ir(111). Because of a band gap in the projected Ir band structure around the graphene K point, the electronic properties of the QDs are dominantly graphenelike. Indeed, we ... [Phys. Rev. Lett. 108, 046801 ] published .
Measuring the Complex Admittance of a Carbon Nanotube Double Quantum Dot: S. J. Chorley, J. Wabnig, Z. V. Penfold-Fitch, K. D. Petersson, J. Frake et al.
We investigate radio-frequency (rf) reflectometry in a tunable carbon nanotube double quantum dot coupled to a resonant circuit. By measuring the in-phase and quadrature components of the reflected rf signal, we are able to determine the complex admittance of the double quantum dot as a function of ... [Phys. Rev. Lett. 108, 036802 ] published .
Ultrafast luminescence kinetics of metallic single-walled carbon nanotubes: Possible evidence for excitonic luminescence: Takeshi Koyama, Satoru Shimizu, Takeshi Saito, Yasumitsu Miyata, Hisanori Shinohara et al.
In metallic systems, strong screening of the Coulomb interaction between an electron and a hole by free electrons largely prevents the formation of an exciton. In one-dimensional metallic systems, however, the screening effect is significantly reduced. Recent theoretical and experimental studies sug ... [Phys. Rev. B 85, 045428 ] published .
Role of structure of C-terminated 4H-SiC(000[overline 1]) surface in growth of graphene layers: Transmission electron microscopy and density functional theory studies: J. Borysiuk, J. Soltys, R. Bozek, J. Piechota, S. Krukowski et al.
The principal structural defects in graphene layers, synthesized on a carbon-terminated face, i.e., the SiC(000[overline 1]) face of a 4H-SiC substrate, are investigated using microscopic methods. Results of high-resolution transmission electron microscopy (HRTEM) reveal their atomic arrangement. Th ... [Phys. Rev. B 85, 045426 ] published .
Exact renormalization group computation of the optical conductivity of graphene: Alessandro Giuliani and Vieri Mastropietro
The optical conductivity of a system of electrons on the honeycomb lattice interacting through a retarded electromagnetic field is computed by exact renormalization-group (RG) methods. By truncating the exact RG expression at one loop we find that the conductivity has the universal value pi/2 times ... [Phys. Rev. B 85, 045420 ] published .
Probing substrate effects in the carbon-projected band structure of graphene on Pt(111) through resonant inelastic x-ray scattering: Srivats Rajasekaran, Sarp Kaya, Toyli Anniyev, Hirohito Ogasawara, and Anders Nilsson
The unoccupied and occupied sigma and pi bands of graphene on Pt(111) were measured using near-edge x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) at the carbon K edge. Elemental specificity and crystal-momentum conservation allows for detection of the dispersive ... [Phys. Rev. B 85, 045419 ] published .
Si intercalation/deintercalation of graphene on 6H-SiC(0001): C. Xia, S. Watcharinyanon, A. A. Zakharov, R. Yakimova, L. Hultman et al.
The intercalation and deintercalation mechanisms of Si deposited on monolayer graphene grown on SiC(0001) substrates and after subsequent annealing steps are investigated using low-energy electron microscopy (LEEM), photoelectron spectroscopy (PES), and micro-low-energy electron diffraction ([mu]-LE ... [Phys. Rev. B 85, 045418 ] published .
Sources of negative tunneling magnetoresistance in multilevel quantum dots with ferromagnetic contacts: Sonja Koller, Milena Grifoni, and Jens Paaske
We analyze distinct sources of spin-dependent energy level shifts and their impact on the tunneling magnetoresistance (TMR) of interacting quantum dots coupled to collinearly polarized ferromagnetic leads. Level shifts due to virtual charge fluctuations can be quantitatively evaluated within a diagr ... [Phys. Rev. B 85, 045313 ] published .
Effects of static charging and exfoliation of layered crystals: M. Topsakal and S. Ciraci
Using a first-principle plane-wave method we investigate the effects of static charging on the structural, electronic, and magnetic properties of suspended, single-layer graphene, graphane, fluorographene, BN, and MoS in a honeycomb structure. The limitations of periodic boundary conditions in the t ... [Phys. Rev. B 85, 045121 ] published .
Skyrme crystal in bilayer and multilayer graphene: Yasuhisa Sakurai and Daijiro Yoshioka
The ground state of the two-dimensional electron systems in Bernal bilayer and ABC-stacked multilayer graphenes in the presence of a strong magnetic field is investigated with the Hartree-Fock approximation. Phase diagrams of the systems are obtained, focusing on charge density wave states including ... [Phys. Rev. B 85, 045108 ] published .
Interface structure of graphene on SiC(000[overline 1]): N. Srivastava, Guowei He, Luxmi, and R. M. Feenstra
Graphene films prepared by heating the SiC(000[overline 1]) surface (the C-face of the {0001} surfaces) in a vacuum or in a Si-rich environment are compared. It is found that different interface structures occur for the two situations. The former yields a well known 3 x 3 reconstructed interface, ... [Phys. Rev. B 85, 041404 ] published .
Ultrafast carrier dynamics and terahertz emission in optically pumped graphene at room temperature: S. Boubanga-Tombet, S. Chan, T. Watanabe, A. Satou, V. Ryzhii et al.
We report, within a picosecond time scale, fast relaxation and relatively slow recombination dynamics of photogenerated electrons and holes in an exfoliated graphene under infrared pulse excitation. We conduct time-domain spectroscopic studies using an optical pump and terahertz probe with an optica ... [Phys. Rev. B 85, 035443 ] published .
Fluctuations, Dynamics, and the Stretch-Coil Transition of Single Actin Filaments in Extensional Flows: Vasily Kantsler and Raymond E. Goldstein
Semiflexible polymers subject to hydrodynamic forcing play an important role in cytoskeletal motions in the cell, particularly when filaments guide molecular motors whose motions create flows. Near hyperbolic stagnation points, filaments experience a competition between bending elasticity and tensio ... [Phys. Rev. Lett. 108, 038103 ] published .
Synthesis of single-component metallic glasses by thermal spray of nanodroplets on amorphous substrates: Qi An, Sheng-Nian Luo, William A. Goddard, III, W. Z. Han, B. Arman et al.
We show that single component metallic glasses can be synthesized by thermal spray coating of nanodroplets onto an amorphous substrate. We demonstrate this using molecular dynamics simulations of nanodroplets up to 30 nm that the spreading of the nanodroplets during impact on a substrate leads to su ... [Appl. Phys. Lett. 100, 041909 (2012)] published Thu Jan 26, 2012.
Numerical demonstration of the reciprocity among elemental relaxation and driven-flow problems for a rarefied gas in a channel: Shigeru Takata and Masashi Oishi
Relaxations from a uniform mass/heat flow and flows driven by an external force/temperature-gradient for a rarefied gas between two parallel plates are studied on the basis of the kinetic theory of gases. By numerical computations of the linearized BhatnagarGrossKrook model of the Boltzmann equation ... [Phys. Fluids 24, 012003 ] published .
Anisotropic Pair Correlations and Structure Factors of Confined Hard-Sphere Fluids: An Experimental and Theoretical Study: K. Nygard, R. Kjellander, S. Sarman, S. Chodankar, E. Perret et al.
We address the fundamental question: how are pair correlations and structure factors of hard-sphere fluids affected by confinement between hard planar walls at close distance? For this purpose, we combine x-ray scattering from colloid-filled nanofluidic channel arrays and first-principles inhomogene ... [Phys. Rev. Lett. 108, 037802 ] published .
Hamiltonian Traffic Dynamics in Microfluidic-Loop Networks: Raphael Jeanneret, Julien-Piera Vest, and Denis Bartolo
Recent microfluidic experiments revealed that large particles advected in a fluidic loop display long-range hydrodynamic interactions. However, the consequences of such couplings on the traffic dynamics in more complex networks remain poorly understood. In this Letter, we focus on the transport of a ... [Phys. Rev. Lett. 108, 034501 ] published .
Entropic Splitter for Particle Separation: D. Reguera, A. Luque, P. S. Burada, G. Schmid, J. M. Rubi et al.
We present a particle separation mechanism which induces the motion of particles of different sizes in opposite directions. The mechanism is based on the combined action of a driving force and an entropic rectification of the Brownian fluctuations caused by the asymmetric form of the channel along w ... [Phys. Rev. Lett. 108, 020604 ] published .
Droplet formation in microfluidic T-junction generators operating in the transitional regime. II. Modeling: Tomasz Glawdel, Caglar Elbuken, and Carolyn L. Ren
This is the second part of a two-part study on the generation of droplets at a microfluidic T-junction operating in the transition regime. In the preceding paper [Phys. Rev. E 85, 016322 (2012)], we presented our experimental observations of droplet formation and decomposed the process into three se ... [Phys. Rev. E 85, 016323 ] published .
Fluid flow due to collective non-reciprocal motion of symmetrically-beating artificial cilia: S. N. Khaderi, J. M. J. den Toonder, and P. R. Onck
Using a magneto-mechanical solid-fluid numerical model for permanently magnetic artificial cilia, we show that the metachronal motion of symmetrically beating cilia establishes a net pressure gradient in the direction of the metachronal wave, which creates a unidirectional flow. The flow generated i ... [Biomicrofluidics 6, 014106 (2012)] published Fri Jan 20, 2012.
A mathematical model of mixing enhancement in microfluidic channel with a constriction under periodic electro-osmotic flow: Zhongbin Xu, Yue Yang, Damien Vadillo, Xiaodong Ruan, and Xin Fu
A microfluidic channel with a constriction produced poor mixing conditions under periodic electro-osmotic flow. However, the mixing performance may be enhanced significantly by altering other parameters. Numerical simulations are used to investigate the effect of the direct current electric field (E ... [Appl. Phys. Lett. 100, 041907 (2012)] published Thu Jan 26, 2012.
Droplet formation in microfluidic T-junction generators operating in the transitional regime. I. Experimental observations: Tomasz Glawdel, Caglar Elbuken, and Carolyn L. Ren
This is the first part of a two-part study on the generation of droplets at a microfluidic T-junction operating in the transition regime where confinement of the droplet creates a large squeezing pressure that influences droplet formation. In this regime, the operation of the T-junction depends on t ... [Phys. Rev. E 85, 016322 ] published .
Electromagnetic propulsion and separation by chirality of nanoparticles in liquids: E. Kirkinis, A. V. Andreev, and B. Spivak
We introduce a new mechanism for the propulsion and separation by chirality of small ferromagnetic particles suspended in a liquid. Under the action of a uniform dc magnetic field H and an ac electric field E isomers with opposite chirality move in opposite directions. Such a mechanism could have a ... [Phys. Rev. E 85, 016321 ] published .
Surface-charge-induced alteration of nanovortex patterning in nanoscale confinements with patterned wettability gradients: Manik Mayur, Debapriya Chakraborty, Jeevanjyoti Chakraborty, and Suman Chakraborty
We characterize the generation of flow vortices in nanoscale confinements under the combined effects of patterned surface charge density and substrate wettability. Using molecular dynamics simulations, we elucidate the effects of ion solvation and steric interactions toward influencing the resultant ... [Phys. Rev. E 85, 016315 ] published .
Synchronous imaging for rapid visualization of complex vibration profiles in electromechanical microresonators: Yoav Linzon, Daniel J. Joe, Bojan Ilic, Juraj Topolancik, Jeevak M. Parpia et al.
Synchronous imaging is used for the dynamic space-domain studies of vibration profiles in capacitively driven, thin n + doped polysilicon microbridges oscillating at rf frequencies. Fast and high-resolution actuation profile measurements of micromachined resonators are useful when significant device ... [J. Appl. Phys. 111, 023507 (2012)] published Fri Jan 20, 2012.
Nonlinear detection mechanism in quantitative atomic force microscopy characterization of high-frequency nanoelectromechanical systems: Marc Serra-Garcia, Francesc Perez-Murano, and Alvaro San Paulo
We investigate the transduction of motion from a nanomechanical resonator to the cantilever/tip probe of an atomic force microscope. Our results show that amplitude-modulated high-frequency vibrations of nanomechanical resonators can be measured by means of a low-resonance frequency cantilever as a ... [Phys. Rev. B 85, 035433 ] published .
Observation of Quantum Motion of a Nanomechanical Resonator: Amir H. Safavi-Naeini, Jasper Chan, Jeff T. Hill, Thiago P. Mayer Alegre, Alex Krause et al.
In this Letter we use resolved sideband laser cooling to cool a mesoscopic mechanical resonator to near its quantum ground state (phonon occupancy 2.60.2), and observe the motional sidebands generated on a second probe laser. Asymmetry in the sideband amplitudes provides a direct measure of the disp ... [Phys. Rev. Lett. 108, 033602 ] published .
Parabolic tapered photonic crystal cavity in silicon: Boris Desiatov, Ilya Goykhman, and Uriel Levy
We demonstrate the design, fabrication, transmission spectrum measurement, and near-field characterization of a parabolic tapered one-dimensional photonic crystal cavity in silicon. The results shows a relatively high quality factor (~43 000), together with a small modal volume of ~1.1(lambda/n). Mo ... [Appl. Phys. Lett. 100, 041112 (2012)] published Wed Jan 25, 2012.
Room temperature, continuous wave lasing in microcylinder and microring quantum dot laser diodes: M. Munsch, J. Claudon, N. S. Malik, K. Gilbert, P. Grosse et al.
We demonstrate room temperature, continuous wave lasing of laser diodes based on AlGaAs whispering gallery mode (WGM) resonators (microcylinder and microring) embedding a quantum dot (QD) active layer. Using InGaAlAs QDs, high-Q (>60 000) lasing modes are observed around 910 nm, up to 50 degrees C. ... [Appl. Phys. Lett. 100, 031111 (2012)] published Fri Jan 20, 2012.
Spiral plasmonic nanoantennas as circular polarization transmission filters: K. A. Bachman, J. J. Peltzer, P. D. Flammer, T. E. Furtak, R. T. Collins et al.
We present simulation and experimental results for easily fabricated spiral plasmonic antenna analogues providing circular polarization selectivity. One circular polarization state is concentrated and transmitted through a subwavelength aperture, while the opposite circular state is blocked. The spe ... [Opt. Express 20, 1308 (2012)] published Tue Jan 24, 2012.
Enhancement of local electromagnetic fields in plasmonic crystals of coaxial metallic nanostructures: Masanobu Iwanaga, Naoki Ikeda, and Yoshimasa Sugimoto
We have experimentally and numerically examined resonant modes in plasmonic crystals (PlCs) of coaxial metallic nanostructures. Resonance enhancements of local electromagnetic (EM) fields were evaluated quantitatively. We clarified that a local mode induced in the coaxial metallic structure shows th ... [Phys. Rev. B 85, 045427 ] published .
Mapping between quantum dot and quantum well lasers: From conventional to spin lasers: Jeongsu Lee, Rafal Oszwaldowski, Christian Gothgen, and Igor Zutic
We explore similarities between the quantum wells and quantum dots used as optical gain media in semiconductor lasers. We formulate a mapping procedure which allows a simpler, often analytical, description of quantum well lasers to study more complex lasers based on quantum dots. The key observation ... [Phys. Rev. B 85, 045314 ] published .
Electron spin synchronization induced by optical nuclear magnetic resonance feedback: M. M. Glazov, I. A. Yugova, and Al. L. Efros
We predict a new physical mechanism to explain the electron spin precession frequency focusing effect recently observed in singly charged quantum dots exposed to a periodic train of resonant circularly polarized short optical pulses [A. Greilich et al., Science 317, 1896 (2007)]. We show that electr ... [Phys. Rev. B 85, 041303 ] published .
Proposed isotropic negative index in three-dimensional optical metamaterials: Boubacar Kante, Kevin O'Brien, Avi Niv, Xiaobo Yin, and Xiang Zhang
A simple route toward achieving an isotropic optical negative index in three dimensions is theoretically proposed. We show that, in contrast with previous studies, the plasmonic ring resonators, symmetrically split with an odd number of gaps, have both degenerate electric and magnetic resonances and ... [Phys. Rev. B 85, 041103 ] published .
Mesoscopic Self-Collimation and Slow Light in All-Positive Index Layered Photonic Crystals: Julien Arlandis, Emmanuel Centeno, Remi Polles, Antoine Moreau, Julien Campos et al.
We demonstrate a mesoscopic self-collimation effect in photonic crystal superlattices consisting of a periodic set of all-positive index 2D photonic crystal and homogeneous layers. We develop an electromagnetic theory showing that diffraction-free beams are observed when the curvature of the optical ... [Phys. Rev. Lett. 108, 037401 ] published .
Backscattering Suppression in Supersonic 1D Polariton Condensates: D. Tanese, D. D. Solnyshkov, A. Amo, L. Ferrier, E. Bernet-Rollande et al.
We investigate the effect of disorder on the propagation of one-dimensional polariton condensates in semiconductor microcavities. We observe a strong suppression of the backscattering produced by the imperfections of the structure when increasing the condensate density. This suppression occurs in th ... [Phys. Rev. Lett. 108, 036405 ] published .
Ultrafast Tilting of the Dispersion of a Photonic Crystal and Adiabatic Spectral Compression of Light Pulses: Daryl M. Beggs, Thomas F. Krauss, L. Kuipers, and Tobias Kampfrath
We demonstrate, by theory and experiment, the ultrafast tilting of the dispersion curve of a photonic-crystal waveguide following the absorption of a femtosecond pump pulse. By shaping the pump-beam cross section with a nanometric shadow mask, different waveguide eigenmodes acquire different spatial ... [Phys. Rev. Lett. 108, 033902 ] published .
Genetic-Algorithm Discovery of a Direct-Gap and Optically Allowed Superstructure from Indirect-Gap Si and Ge Semiconductors: Mayeul d'Avezac, Jun-Wei Luo, Thomas Chanier, and Alex Zunger
Combining two indirect-gap materialswith different electronic and optical gapsto create a direct gap material represents an ongoing theoretical challenge with potentially rewarding practical implications, such as optoelectronics integration on a single wafer. We provide an unexpected solution to thi ... [Phys. Rev. Lett. 108, 027401 ] published .
Broadband Light Harvesting Nanostructures Robust to Edge Bluntness: Yu Luo, Dang Yuan Lei, Stefan A. Maier, and J. B. Pendry
Metallic structures with sharp corners harvest the energy of incident light through plasmonic resonances, concentrating it in the corners and greatly increasing the local energy density. Despite its wide array of applications, this effect is normally strongly dependent on how sharp the corners are, ... [Phys. Rev. Lett. 108, 023901 ] published .
Broadband Light Bending with Plasmonic Nanoantennas: Xingjie Ni, Naresh K. Emani, Alexander V. Kildishev, Alexandra Boltasseva, and Vladimir M. Shalaev
The precise manipulation of a propagating wave using phase control is a fundamental building block of optical systems. The wavefront of a light beam propagating across an interface can be modified arbitrarily by introducing abrupt phase changes. We experimentally demonstrated unparalleled wavefront ... [Science 335, 427 (2012)] published Tue Jan 24, 2012.
An All-Silicon Passive Optical Diode: Li Fan, Jian Wang, Leo T. Varghese, Hao Shen, Ben Niu et al.
A passive optical diode effect would be useful for on-chip optical information processing but has been difficult to achieve. Using a method based on optical nonlinearity, we demonstrate a forward-backward transmission ratio of up to 28 decibels within telecommunication wavelengths. Our device, which ... [Science 335, 447 (2012)] published Tue Jan 24, 2012.
Scanning probe microscopy imaging of metallic nanocontacts: D. Stoffler, S. Fostner, P. Grutter, and R. Hoffmann-Vogel
We show scanning probe microscopy measurements of metallic nanocontacts between controlled electromigration cycles. The nanowires used for the thinning process are fabricated by shadow evaporation. The highest resolution obtained using scanning force microscopy is about 3 nm. During the first few el ... [Phys. Rev. B 85, 033404 ] published .
Magnetic study of CuMnO (0 <= x <= 0.08) nanoparticles: Shahzad Hussain, A. Mumtaz, S. K. Hasanain, and M. Usman
CuMnO (0 <= x <= 0.08) nanoparticles were synthesized by a coprecipitation method. Powder x ray analysis reveals that samples show a pure CuO phase for x <= 0.06 and the appearance of a secondary phase CuMnO for x > 0.06. The unit cell volume expands with increasing Mn concentration up to x = 0.06 a ... [J. Appl. Phys. 111, 023908 (2012)] published Mon Jan 23, 2012.
Spin transport in memristive devices: Hyuk-Jae Jang, Oleg A. Kirillov, Oana D. Jurchescu, and Curt A. Richter
We report on electron spin transport through electrochemically precipitated copper filaments formed in TaO memristive devices consisting of Co/TaO/Cu/Py with crossbar-type electrode geometry. The devices show memristive behavior having a typical OFF/ON resistance ratio of 10. Magnetoresistance measu ... [Appl. Phys. Lett. 100, 043510 (2012)] published Thu Jan 26, 2012.
Temperature evolution of spin accumulation detected electrically in a nondegenerated silicon channel: Y. Ando, K. Kasahara, S. Yamada, Y. Maeda, K. Masaki et al.
We study temperature evolution of spin-accumulation signals obtained by the three-terminal Hanle-effect measurements in a nondegenerated silicon channel with a Schottky-tunnel-barrier contact. We find the clear difference in the temperature-dependent spin signals between spin-extraction and spin-inj ... [Phys. Rev. B 85, 035320 ] published .
Nanoscale inhomogeneities: A new path toward high Curie temperature ferromagnetism in diluted materials: Akash Chakraborty, Richard Bouzerar, Stefan Kettemann, and Georges Bouzerar
Room-temperature ferromagnetism has been one of the most sought after topics in today's emerging field of spintronics. It is strongly believed that defect- and inhomogeneity-free sample growth should be the optimal route for achieving room-temperature ferromagnetism, and huge efforts are made in ord ... [Phys. Rev. B 85, 014201 ] published .
Tunable Resistivity of Individual Magnetic Domain Walls: J. H. Franken, M. Hoeijmakers, H. J. M. Swagten, and B. Koopmans
Despite the relevance of current-induced magnetic domain wall (DW) motion for new spintronics applications, the exact details of the current-domain wall interaction are not yet understood. A property intimately related to this interaction is the intrinsic DW resistivity. Here, we investigate experim ... [Phys. Rev. Lett. 108, 037205 ] published .
Transverse focusing of spin-polarized photocurrents: Juerong Li, A. M. Gilbertson, K. L. Litvinenko, L. F. Cohen, and S. K. Clowes
We measure transverse magnetically focused photocurrent signals in an InSb/InAlSb quantum well device. Using optical spin orientation by modulated circularly polarized light an electron spin-dependent signal is observed due to the spin-orbit interaction. Simulations of the focusing signal are perfor ... [Phys. Rev. B 85, 045431 ] published .
Magnetization dynamics and cone angle precession in permalloy rectangles: Nils Kuhlmann, Andreas Vogel, and Guido Meier
Magnetization dynamics in pairs of submicrometer-sized permalloy rectangles are studied by means of broadband-ferromagnetic resonance measurements. The coupling strength of neighboring elements depends on their center-to-center distance. The stray field of one rectangle decreases the local effective ... [Phys. Rev. B 85, 014410 ] published .
Symmetry and nonstoichiometry as possible origins of ferromagnetism in nanoscale oxides: Takashi Uchino and Toshinobu Yoko
We show through density functional theory calculations that extended magnetic states can inherently occur in oxides as the size of the crystals is reduced down to the nanometer scale. In nanoscale systems, some crystallographically perfect MgO crystallites paradoxically result in nonstoichiometric c ... [Phys. Rev. B 85, 012407 ] published .
Emergent phenomena at oxide interfaces: H. Y. Hwang, Y. Iwasa, M. Kawasaki, B. Keimer, N. Nagaosa et al.
Recent technical advances in the atomic-scale synthesis of oxide heterostructures have provided a fertile new ground for creating novel states at their interfaces. Different symmetry constraints can be used to design structures exhibiting phenomena not found in the bulk constituents. A characteristi ... [Nature Mater. 11, 103 (2012)] published Thu Jan 26, 2012.
Shot noise induced by electron-nuclear spin-flip scattering in a nonequilibrium quantum wire: Kensaku Chida, Masayuki Hashisaka, Yoshiaki Yamauchi, Shuji Nakamura, Tomonori Arakawa et al.
We study the shot noise (nonequilibrium current fluctuation) associated with dynamic nuclear polarization in a nonequilibrium quantum wire (QW) fabricated in a two-dimensional electron gas. We observe that the spin-polarized conductance quantization of the QW in the integer quantum Hall regime colla ... [Phys. Rev. B 85, 041309 ] published .
Measurement of a Pauli and Orbital Paramagnetic State in Bulk Gold Using X-Ray Magnetic Circular Dichroism Spectroscopy: Motohiro Suzuki, Naomi Kawamura, Hayato Miyagawa, Jose S. Garitaonandia, Yoshiyuki Yamamoto et al.
We show that bulk gold (Au) exhibits temperature-independent paramagnetism in an external magnetic field by x-ray magnetic circular dichroism spectroscopy at the Au L and L edges. Using the sum-rule analysis, we obtained a magnetic moment of 1.3 x 10 [mu]/atom in an external magnetic field of 10 T ... [Phys. Rev. Lett. 108, 047201 ] published .
Magnetism in nanometer-thick magnetite: Matteo Monti, Benito Santos, Arantzazu Mascaraque, Oscar Rodriguez de la Fuente, Miguel Angel Nino et al.
The oldest known magnetic material, magnetite, is of current interest for use in spintronics as a thin film. An open question is how thin can magnetite films be and still retain the robust ferrimagnetism required for many applications. We have grown 1-nm-thick magnetite crystals and characterized th ... [Phys. Rev. B 85, 020404 ] published .
Topological Hubbard Model and Its High-Temperature Quantum Hall Effect: Titus Neupert, Luiz Santos, Shinsei Ryu, Claudio Chamon, and Christopher Mudry
The quintessential two-dimensional lattice model that describes the competition between the kinetic energy of electrons and their short-range repulsive interactions is the repulsive Hubbard model. We study a time-reversal symmetric variant of the repulsive Hubbard model defined on a planar lattice: ... [Phys. Rev. Lett. 108, 046806 ] published .
Quantum phase transitions in ultrathin films of three-dimensional topological insulators in the presence of an electrostatic potential and a Zeeman field: Huichao Li, L. Sheng, and D. Y. Xing
We investigate transport properties of the surface states of three-dimensional topological insulator thin films in the presence of an electrostatic potential gamma and a spin-splitting Zeeman field g. It is shown that there exist a quantum pseudospin Hall phase, a quantum anomalous Hall phase, and a ... [Phys. Rev. B 85, 045118 ] published .
Signature of interaction in dc transport of ac-gated quantum spin Hall edge states: Fabrizio Dolcini
In the presence of a scattering potential, electron transport in a quantum wire is known to be dramatically modified by backward-scattering and unaffected by forward-scattering processes. We show that the scenario is quite different in quantum spin Hall edge states coupled at a constriction. The hel ... [Phys. Rev. B 85, 033306 ] published .
Hydrodynamic rectified drag current in a quantum wire induced by Wigner crystallization: M. Yamamoto, H. Takagi, M. Stopa, and S. Tarucha
We measure Coulomb drag between displaced parallel quantum wires fabricated on a high-mobility two-dimensional electron gas using a split-gate technique. We observe a rectified Coulomb drag, in which the sign of the drag current is the same irrespective of the current direction in the drive wire, wh ... [Phys. Rev. B 85, 041308 ] published .
Single-Shot Measurement of Triplet-Singlet Relaxation in a Si/SiGe Double Quantum Dot: J. R. Prance, Zhan Shi, C. B. Simmons, D. E. Savage, M. G. Lagally et al.
We investigate the lifetime of two-electron spin states in a few-electron Si/SiGe double dot. At the transition between the (1,1) and (0,2) charge occupations, Pauli spin blockade provides a readout mechanism for the spin state. We use the statistics of repeated single-shot measurements to extract t ... [Phys. Rev. Lett. 108, 046808 ] published .
Enhancement of the Kondo Effect through Rashba Spin-Orbit Interactions: Mahdi Zarea, Sergio E. Ulloa, and Nancy Sandler
We study a one-orbital Anderson impurity in a two-dimensional electron bath with Rashba spin-orbit interactions in the Kondo regime. The spin SU(2) symmetry-breaking term couples the impurity to a two-band electron gas. A Schrieffer-Wolff transformation shows the existence of the Dzyaloshinsky-Moriy ... [Phys. Rev. Lett. 108, 046601 ] published .
Transmission Eigenvalues and the Bare Conductance in the Crossover to Anderson Localization: Zhou Shi and Azriel Z. Genack
We measure the field transmission matrix t for microwave radiation propagating through random waveguides in the crossover to Anderson localization. From these measurements, we determine the dimensionless conductance g and the individual eigenvalues tau of the transmission matrix tt whose sum equals ... [Phys. Rev. Lett. 108, 043901 ] published .
Cold-Field Switching in PVDF-TrFE Ferroelectric Polymer Nanomesas: Igor Stolichnov, Peter Maksymovych, Evgeny Mikheev, Sergei V. Kalinin, Alexander K. Tagantsev et al.
Polarization reversal in ferroelectric nanomesas of polyvinylidene fluoride with trifluoroethylene has been probed by ultrahigh vacuum piezoresponse force microscopy in a wide temperature range from 89 to 326 K. In dramatic contrast to the macroscopic data, the piezoresponse force microscopy local s ... [Phys. Rev. Lett. 108, 027603 ] published .
Spin-dependent avoided-crossing effect on quantum-well states in Al/W(110): A. G. Rybkin, A. M. Shikin, D. Marchenko, A. Varykhalov, and O. Rader
Despite their low atomic number, Al films show large spin-orbit splittings when grown on W(110). Our spin- and angle-resolved photoemission experiment reveals two types of spin-orbit split states: quantum-well states (QWSs) with small Rashba splitting proportional to the electron wave vector in the ... [Phys. Rev. B 85, 045425 ] published .
Experimental evidence for Luttinger liquid behavior in sufficiently long GaAs V-groove quantum wires: E. Levy, I. Sternfeld, M. Eshkol, M. Karpovski, B. Dwir et al.
We have measured the temperature dependence of the conductance of long V-groove quantum wires fabricated using GaAs/AlGaAs heterostructures, in a wide temperature range (200 mK
Phonon-assisted relaxation between hole states in quantum dot molecules: Krzysztof Gawarecki and Pawel Machnikowski
We study theoretically phonon-assisted relaxation and inelastic tunneling of holes in a double quantum dot. We derive hole states and relaxation rates from kp Hamiltonians and show that there is a finite distance between the dots where lifetimes of hole states are very long, which is related to vani ... [Phys. Rev. B 85, 041305 ] published .
Signatures of Rashba spin-orbit interaction in the superconducting proximity effect in helical Luttinger liquids: Pauli Virtanen and Patrik Recher
We consider the superconducting proximity effect in a helical Luttinger liquid at the edge of a two-dimensional (2D) topological insulator, and derive the low-energy Hamiltonian for an edge state tunnel-coupled to an s-wave superconductor. In addition to correlations between the left- and right-movi ... [Phys. Rev. B 85, 035310 ] published .
Nonadiabatic electron pumping through interacting quantum dots: Alexander Croy, Ulf Saalmann, Alexis R. Hernandez, and Caio H. Lewenkopf
We study nonadiabatic charge pumping through single-level quantum dots taking into account Coulomb interactions. We show how a truncated set of equations of motion can be propagated in time by means of an auxiliary-mode expansion. This formalism is capable of treating time-dependent electronic trans ... [Phys. Rev. B 85, 035309 ] published .
Hybridization of wave functions in one-dimensional localization: D. A. Ivanov, M. A. Skvortsov, P. M. Ostrovsky, and Ya. V. Fominov
A quantum particle can be localized in a disordered potential, the effect known as Anderson localization. In such a system, correlations of wave functions at very close energies may be described, due to Mott, in terms of a hybridization of localized states. We revisit this hybridization description ... [Phys. Rev. B 85, 035109 ] published .
Localization and mobility gap in the topological Anderson insulator: Yan-Yang Zhang, Rui-Lin Chu, Fu-Chun Zhang, and Shun-Qing Shen
It has been proposed that disorder may lead to a new type of topological insulator, called the topological Anderson insulator (TAI). Here we examine the physical origin of this phenomenon. We calculate the topological invariants and density of states of the disordered model in a supercell of a two-d ... [Phys. Rev. B 85, 035107 ] published .
Probing the spin states of three interacting electrons in quantum dots: A. Gamucci, V. Pellegrini, A. Singha, A. Pinczuk, L. N. Pfeiffer et al.
We observe a low-lying sharp spin mode of three interacting electrons in an array of nanofabricated AlGaAs/GaAs quantum dots by means of resonant inelastic light scattering. The finding is enabled by a suppression of the inhomogeneous contribution to the excitation spectra obtained by reducing the n ... [Phys. Rev. B 85, 033307 ] published .
Effects of fermion flavor on exciton condensation in double-layer systems: J. Shumway and Matthew J. Gilbert
We use a fermionic path-integral quantum Monte Carlo framework to study the effects of fermion flavor on the physical properties of dipolar exciton condensates in double-layer systems. We find that by including spin in the system the effective interlayer interaction strength is weakened, yet this ha ... [Phys. Rev. B 85, 033103 ] published .
Conductance fluctuations in chaotic systems with tunnel barriers: Daniel Waltner, Jack Kuipers, Philippe Jacquod, and Klaus Richter
Quantum effects are expected to disappear in the short-wavelength, semiclassical limit. As a matter of fact, recent investigations of transport through quantum chaotic systems have demonstrated the exponential suppression of the weak localization corrections to the conductance and of the Fano factor ... [Phys. Rev. B 85, 024302 ] published .
Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor: O.-P. Saira, A. Kemppinen, V. F. Maisi, and J. P. Pekola
The achievable fidelity of many nanoelectronic devices based on superconducting aluminum is limited by either the density of residual nonequilibrium quasiparticles n or the density of quasiparticle states in the gap, characterized by Dynes parameter gamma. We infer upper bounds n<0.033 [mu]m and ga ... [Phys. Rev. B 85, 012504 ] published .
Real-time simulation of finite-frequency noise from a single-electron emitter: T. Jonckheere, T. Stoll, J. Rech, and T. Martin
We study the real-time emission of single electrons from a quantum dot coupled to a one dimensional conductor, using exact diagonalization on a discrete tight-binding chain. We show that, from the calculation of the time evolution of the one-electron states, we have simple access to all the relevant ... [Phys. Rev. B 85, 045321 ] published .
General method for calculating the universal conductance of strongly correlated junctions of multiple quantum wires: Armin Rahmani, Chang-Yu Hou, Adrian Feiguin, Masaki Oshikawa, Claudio Chamon et al.
We develop a method to extract the universal conductance of junctions of multiple quantum wires, a property of systems connected to reservoirs, from static ground-state computations in closed finite systems. The method is based on a key relationship, derived within the framework of boundary conforma ... [Phys. Rev. B 85, 045120 ] published .
Quantized nu=5/2 State in a Two-Subband Quantum Hall System: J. Nuebler, B. Friess, V. Umansky, B. Rosenow, M. Heiblum et al.
The evolution of the fractional quantum Hall state at filling 5/2 is studied in density tunable two-dimensional electron systems formed in wide wells in which it is possible to induce a transition from single- to two-subband occupancy. In 80 and 60 nm wells, the quantum Hall state at 5/2 filling of ... [Phys. Rev. Lett. 108, 046804 ] published .
Coherent singlet-triplet oscillations in a silicon-based double quantum dot: B. M. Maune, M. G. Borselli, B. Huang, T. D. Ladd, P. W. Deelman et al.
Silicon is more than the dominant material in the conventional microelectronics industry: it also has potential as a host material for emerging quantum information technologies. Standard fabrication techniques already allow the isolation of single electron spins in silicon transistor-like devices. ... [Nature 481, 344 (2012)] published Fri Jan 20, 2012.
Gating the Charge State of Single Molecules by Local Electric Fields: I. Fernandez-Torrente, D. Kreikemeyer-Lorenzo, A. Strozecka, K. J. Franke, and J. I. Pascual
The electron-acceptor molecule TCNQ is found in either of two distinct integer charge states when embedded into a monolayer of a charge transfer complex on a gold surface. Scanning tunneling spectroscopy measurements identify these states through the presence or absence of a zero-bias Kondo resonanc ... [Phys. Rev. Lett. 108, 036801 ] published .
Electron-phonon scattering in topological insulator thin films: Sebastien Giraud, Arijit Kundu, and Reinhold Egger
We present a theoretical study of electron-phonon scattering effects in thin films made of a strong topological insulator. The phonons are modeled by isotropic elastic continuum theory with stress-free boundary conditions, and the interaction with the helical surface Dirac fermions is mediated by th ... [Phys. Rev. B 85, 035441 ] published .
Growth sector dependence and mechanism of stress formation in epitaxial diamond growth: M. Fischer, S. Gsell, M. Schreck, and A. Bergmaier
Stress generation in epitaxial diamond growth was investigated by [mu]-Raman spectroscopy and high resolution x-ray diffraction. Intrinsic stress could be varied systematically from compressive to tensile covering a huge range of 5 GPa. The temperature-stress curve for growth on {111}-sectors as com ... [Appl. Phys. Lett. 100, 041906 (2012)] published Thu Jan 26, 2012.
Why Nanoprojectiles Work Differently than Macroimpactors: The Role of Plastic Flow: Christian Anders, Eduardo M. Bringa, Gerolf Ziegenhain, Giles A. Graham, J. Freddy Hansen et al.
Atomistic simulation data on crater formation due to the hypervelocity impact of nanoprojectiles of up to 55 nm diameter and with targets containing up to 1.1 x 10 atoms are compared to available experimental data on [mu]m-, mm-, and cm-sized projectiles. We show that previous scaling laws do not ho ... [Phys. Rev. Lett. 108, 027601 ] published .
Confinement effects on the vibrational properties of III-V and II-VI nanoclusters: Peng Han and Gabriel Bester
We present a first-principles study of the confinement effects on the vibrational properties of thousand atoms (radii up to 16.2 A) colloidal III-V and II-VI nanoclusters. We describe how the molecular-type vibrations, such as surface-optical, surface-acoustic, and coherent acoustic modes, coexist a ... [Phys. Rev. B 85, 041306 ] published .
Gallium-droplet behaviors of self-catalyzed GaAs nanowires: A transmission electron microscopy study: Young Heon Kim, Dong Woo Park, and Sang Jun Lee
When the arsenic (As) precursor was supplied during cool down, the gallium (Ga) droplets on top of GaAs nanowires (NWs) were extinct on the final products. The Ga droplets were conserved, and their behaviors depended on the size of the NWs when the As supply was cut off during the cooling: The conta ... [Appl. Phys. Lett. 100, 033117 (2012)] published Fri Jan 20, 2012.
Direct patterning of functional interfaces in oxide heterostructures: N. Banerjee, M. Huijben, G. Koster, and G. Rijnders
We report on the direct patterning of high-quality structures incorporating the LaAlO-SrTiO interface by an epitaxial-liftoff technique avoiding any reactive ion beam etching. Detailed studies of temperature dependent magnetotransport properties were performed on the patterned heterostructures with ... [Appl. Phys. Lett. 100, 041601 (2012)] published Mon Jan 23, 2012.
Colloquium: Stimulating uncertainty: Amplifying the quantum vacuum with superconducting circuits: P. D. Nation, J. R. Johansson, M. P. Blencowe, and Franco Nori
The ability to generate particles from the quantum vacuum is one of the most profound consequences of Heisenberg's uncertainty principle. Although the significance of vacuum fluctuations can be seen throughout physics, the experimental realization of vacuum amplification effects has until now been l ... [Rev. Mod. Phys. 84, 1 ] published .

Virtual Journal of Ultrafast Science

Three dimensional laser microfabrication in diamond using a dual adaptive optics system: Richard D. Simmonds, Patrick S. Salter, Alexander Jesacher, and Martin J. Booth
Femtosecond laser fabrication of controlled three dimensional structures deep in the bulk of diamond is facilitated by a dual adaptive optics system. A deformable mirror is used in parallel with a liquid crystal spatial light modulator to compensate the extreme aberrations caused by the refractive i ... [Opt. Express 19, 24122 (2011)] published Thu Dec 1, 2011.
Low-loss channel optical waveguide fabrication in Nd-doped silicate glasses by femtosecond laser direct writing: Shi-Ling Li, Peigao Han, Meng Shi, Yicun Yao, Bing Hu et al.
Optical waveguides were fabricated in neodymium-doped silicate glass by using a low-repetition-rate (1 kHz) femtosecond laser inscription. Two different types of waveguide structure are fabricated. In the first, guiding occurs in the focal spot. In the second, guiding occurs in the region between th ... [Opt. Express 19, 23958 (2011)] published Thu Dec 1, 2011.
All-optical 1st and 2nd order integration on a chip: Marcello Ferrera, Yongwoo Park, Luca Razzari, Brent E. Little, Sai T. Chu et al.
We demonstrate all-optical temporal integration of arbitrary optical waveforms with temporal features as short as ~1.9ps. By using a four-port micro-ring resonator based on CMOS compatible doped glass technology we perform the 1st- and 2nd-order cumulative time integral of optical signals over a ban ... [Opt. Express 19, 23153 (2011)] published Thu Dec 1, 2011.
Nonlinear-optical brain anatomy by harmonic-generation and coherent Raman microscopy on a compact femtosecond laser platform: Lyubov V. Doronina-Amitonova, Aleksandr A. Lanin, Olga I. Ivashkina, Marina A. Zots, Andrei B. Fedotov et al.
An extended-cavity Cr:forsterite laser is integrated with a photonic-crystal fiber soliton frequency shifter and a periodically poled lithium niobate spectrum compressor for simultaneous harmonic-generation and coherent Raman brain imaging. Adapting the laser beam focusing geometry to the tissue mor ... [Appl. Phys. Lett. 99, 231109 (2011)] published Thu Dec 8, 2011.
Attoclock reveals natural coordinates of the laser-induced tunnelling current flow in atoms: Adrian N. Pfeiffer, Claudio Cirelli, Mathias Smolarski, Darko Dimitrovski, Mahmoud Abu-samha et al.
In the research area of strong-laser-field interactions and attosecond science, tunnelling of an electron through the barrier formed by the electric field of the laser and the atomic potential is typically assumed to be the initial key process that triggers subsequent dynamics. Here we use the atto ... [Nature Phys. 8, 76 (2011)] published Thu Dec 22, 2011.
Probing dielectric-response effects with attosecond time-resolved streaked photoelectron spectroscopy of metal surfaces: C.-H. Zhang and U. Thumm
The release of conduction-band electrons from a metal surface by a subfemtosecond extreme ultraviolet (XUV) pulse and their propagation through the solid provoke a dielectric response in the solid that acts back on the photoelectron wave packet. We calculated the (wake) potential associated with thi ... [Phys. Rev. A 84, 063403 ] published .
Optimization of three-color laser field for the generation of single ultrashort attosecond pulse: Peng-Cheng Li, I-Lin Liu, and Shih-I Chu
We present an efficient and realizable scheme for the generation of an ultrashort single attosecond (as) pulse. The feasibility of such a scheme is demonstrated by solving accurately the time-dependent Schrodinger equation using the time-dependent generalized pseudospectral (TDGPS) method. This sche ... [Opt. Express 19, 23857 (2011)] published Thu Dec 1, 2011.
Theory of ac Stark splitting in core-resonant Auger decay in strong x-ray fields: L. A. A. Nikolopoulos, T. J. Kelly, and J. T. Costello
In this work we report the modification of the normal Auger line shape under the action of an intense x-ray radiation. Under strong Rabi-type coupling of the core, the Auger line profile develops into a doublet structure with an energy separation mainly determined by the relative strength of the Rab ... [Phys. Rev. A 84, 063419 ] published .
Attosecond control of dissociative ionization of O molecules: W. Siu, F. Kelkensberg, G. Gademann, A. Rouzee, P. Johnsson et al.
We demonstrate that dissociative ionization of O can be controlled by the relative delay between an attosecond pulse train (APT) and a copropagating infrared (IR) field. Our experiments reveal a dependence of both the branching ratios between a range of electronic states and the fragment angular dis ... [Phys. Rev. A 84, 063412 ] published .
Time delay between photoemission from the 2p and 2s subshells of neon: L. R. Moore, M. A. Lysaght, J. S. Parker, H. W. van der Hart, and K. T. Taylor
The R-matrix incorporating time (RMT) method is a method developed recently for solving the time-dependent Schrodinger equation for multielectron atomic systems exposed to intense short-pulse laser light. We have employed the RMT method to investigate the time delay in the photoemission of an electr ... [Phys. Rev. A 84, 061404 ] published .
Compression methods for XUV attosecond pulses: Mark Mero, Fabio Frassetto, Paolo Villoresi, Luca Poletto, and Katalin Varju
Attosecond extreme-ultraviolet (XUV) pulses generated in gases via high-order harmonic generation typically carry an intrinsic positive chirp. Compression of such pulses has been demonstrated using metallic transmission filters, a method with very limited tunability. We compare here the compression ... [Opt. Express 19, 23420 (2011)] published Thu Dec 1, 2011.
Optimizing intracavity high harmonic generation for XUV fs frequency combs: Jane Lee, David R. Carlson, and R. Jason Jones
Previous work has shown that use of a passive enhancement cavity designed for ultrashort pulses can enable the up-conversion of the fs frequency comb into the extreme ultraviolet (XUV) spectral region utilizing the highly nonlinear process of high harmonic generation. This promising approach for an ... [Opt. Express 19, 23315 (2011)] published Thu Dec 1, 2011.
Precise evaluation of polarization mode dispersion by separation of even- and odd-order effects in quantum interferometry: A. Fraine, D. S. Simon, O. Minaeva, R. Egorov, and A. V. Sergienko
The use of quantum correlations between photons to separate measure even- and odd-order components of polarization mode dispersion (PMD) and chromatic dispersion in discrete optical elements is investigated. Two types of apparatus are discussed which use coincidence counting of entangled photon pair ... [Opt. Express 19, 22820 (2011)] published Thu Dec 1, 2011.
The influence of plasma defocusing in high harmonic generation: Chien-Jen Lai and Franz X. Kartner
We numerically investigate the influence of plasma defocusing in high harmonic generation (HHG) by solving the first-order wave equation in an ionized medium and defining an enhancement factor to quantitatively analyze the influence of plasma defocusing. While degrading the driver pulse intensity, p ... [Opt. Express 19, 22377 (2011)] published Thu Dec 1, 2011.
Time-and-energy-resolved measurement of Auger cascades following Kr 3d excitation by attosecond pulses: A Verhoef, A Mitrofanov, X Nguyen, M Krikunova, S Fritzsche et al.
We show that attosecond metrology has evolved from proof-of-principle experiments to a level where complex processes can be resolved in time that cannot be accessed using any other existing technique. The cascaded Auger decay following ionization and excitation of the 3d-subshell in Kr with subfemto ... [New J. Phys. 13, 113003 (2011)] published Thu Dec 1, 2011.
Efficient control of quantum paths via dual-gas high harmonic generation: A Willner, F Tavella, M Yeung, T Dzelzainis, C Kamperidis et al.
The accurate control of the relative phase of multiple distinct sources of radiation produced by high harmonic generation is of central importance in the continued development of coherent extreme UV (XUV) and attosecond sources. Here, we present a novel approach which allows extremely accurate phase ... [New J. Phys. 13, 113001 (2011)] published Thu Dec 1, 2011.
Ultrafast nonlinear optics in gas-filled hollow-core photonic crystal fibers [Invited]: John C. Travers, Wonkeun Chang, Johannes Nold, Nicolas Y. Joly, and Philip St. J. Russell
We review the use of hollow-core photonic crystal fibers (PCFs) in the field of ultrafast gas-based nonlinear optics, including recent experiments, numerical modeling, and a discussion of future prospects. Concentrating on broadband guiding kagome-style h ... [J. Opt. Soc. Am. B 28, A11 (2011)] published Fri Dec 23, 2011.
Control of high-order harmonics for attoscience using a static-electric-field pattern: Carles Serrat
Quantum control in high-order-harmonic generation is considered theoretically by using a spatial distribution of static electric fields along the propagation direction of the driving field. It is shown that the trajectories of the electrons during its acceleration by the laser field in the high-harm ... [Phys. Rev. A 84, 061803 ] published .
High-order-harmonic generation in gas with a flat-top laser beam: W. Boutu, T. Auguste, O. Boyko, I. Sola, Ph. Balcou et al.
We present experimental and numerical results on high-order-harmonic generation with a flat-top laser beam. We show that a simple binary tunable phase plate, made of two concentric glass plates, can produce a flat-top profile at the focus of a Gaussian infrared beam. Both experiments and numerical c ... [Phys. Rev. A 84, 063406 ] published .
Conical emission from laser filaments and higher-order Kerr effect in air: P. Bejot and J. Kasparian
We numerically investigate the conical emission (CE) from ultrashort laser filaments, both considering and disregarding the higher-order Kerr effect (HOKE). While the consideration of HOKE has almost no influence on the predicted CE from collimated beams, differences arise for tightly focused beams. ... [Opt. Lett. 36, 4812 (2011)] published Tue Dec 20, 2011.
Kadomtsev-Petviashvili solitons propagation in a plasma system with superthermal and weakly relativistic effects: Hafeez-Ur-Rehman, Asif Shah, S. Mahmood, and Q. Haque
Two dimensional (2D) solitons are studied in a plasma system comprising of relativistically streaming ions, kappa distributed electrons, and positrons. Kadomtsev-Petviashvili (KP) equation is derived through the reductive perturbation technique. Analytical solution of the KP equation has been studie ... [Phys. Plasmas 18, 122302 (2011)] published Tue Dec 13, 2011.
Molecular dynamic studies on anisotropy of atomic cluster explosions driven by few-cycle intense lasers: Gaurav Mishra and N. Gupta
The dynamical processes following the irradiation of various argon clusters (1658) with high-intensity lasers (510W/cm310W/cm) of femtosecond pulse durations (5100fs) are modelled using a three-dimensional relativistic time-dependent molecular dynamic approach. Various parameters governing the clust ... [EPL 96, 63001 (2011)] published Thu Dec 22, 2011.
Enhanced thermal self-focusing of a Gaussian laser beam in a collisionless plasma: Devki Nandan Gupta and Hyyong Suk
Theory given by Wang-Zhou [Phys. Plasmas 18, 043101 (2011)] for the thermal self-focusing of a Gaussian laser beam in a collisionless plasma is revisited by including the effect of a localized upward plasma-density ramp. As the equilibrium electron density is an increasing function of the distance o ... [Phys. Plasmas 18, 124501 (2011)] published Wed Dec 7, 2011.
Equation of motion with radiation reaction in ultrarelativistic laser-electron interactions: Keita Seto, Hideo Nagatomo, James Koga, and Kunioki Mima
The intensity of the ultra-short pulse lasers has reached 10 W/cm owing to the advancements of laser technology. When the motion of an electron becomes relativistic, bremsstrahlung accompanies it. The energy from this bremsstrahlung corresponds to the energy loss of the electron; therefore, the moti ... [Phys. Plasmas 18, 123101 (2011)] published Fri Dec 2, 2011.
Measurements and simulations of shock wave generated plasma-vacuum interface: D. Kaganovich, M. H. Helle, D. F. Gordon, and A. Ting
A controlled gradient gas jet was designed, constructed, and tested at the Naval Research Laboratory for the generation of high density and sharp gradient plasma regions. The gas jet uses a laser-generated shock wave to control the density gradient at the vacuum and neutral gas interface. The length ... [Phys. Plasmas 18, 120701 (2011)] published Wed Dec 21, 2011.
Study of self-generated magnetic fields in laser produced plasmas using a three-channel polaro-interferometer: Y. B. S. R. Prasad, S. Barnwal, E. A. Bolkhovitinov, P. A. Naik, M. P. Kamath et al.
Self-generated magnetic fields produced in laser plasmas at moderate laser intensities have been measured using a three-channel polaro-interferometer. The main elements of this device are two birefringent calcite wedges placed between two crossed polarizers. Using this device, the spatial profiles o ... [Rev. Sci. Instrum. 82, 123506 (2011)] published Fri Dec 23, 2011.
A novel zirconium Kalpha imager for high energy density physics research: K. U. Akli, M. Sanchez del Rio, S. Jiang, M. S. Storm, A. Krygier et al.
We report on the development and characterization of a zirconium Kalpha imager for high energy density physics research. The imager consists of a spherically bent quartz crystal operating at 15.7 keV photon energy. We compare the performance of the imager in terms of integrated reflectivity (R) and ... [Rev. Sci. Instrum. 82, 123503 (2011)] published Mon Dec 12, 2011.
Energetics and energy scaling of quasi-monoenergetic protons in laser radiation pressure acceleration: Tung-Chang Liu, Xi Shao, Chuan-Sheng Liu, Jao-Jang Su, Bengt Eliasson et al.
Theoretical and computational studies of the ion energy scaling of the radiation pressure acceleration of an ultra-thin foil by short pulse intense laser irradiation are presented. To obtain a quasi-monoenergetic ion beam with an energy spread of less than 20%, two-dimensional particle-in-cell simul ... [Phys. Plasmas 18, 123105 (2011)] published Thu Dec 29, 2011.
Modeling of 10 GeV-1 TeV laser-plasma accelerators using Lorentz boosted simulations: J.-L. Vay, C. G. R. Geddes, E. Esarey, C. B. Schroeder, W. P. Leemans et al.
Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [J.-L. Vay, Phys. Rev. Lett. 98, 130405 (2007)] allows direct and efficient full-scale modeling of deeply depleted and beam loaded laser-plasma stages of 10 GeV-1 TeV (parameters not computationally accessible otherwise ... [Phys. Plasmas 18, 123103 (2011)] published Tue Dec 13, 2011.
Hollow-core photonic band gap fibers for particle acceleration: Robert J. Noble, James E. Spencer, and Boris T. Kuhlmey
Photonic band gap (PBG) dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM) accelerating fields and a channel for the ch ... [Phys. Rev. ST Accel. Beams 14, 121303 ] published .
Laser accelerated protons captured and transported by a pulse power solenoid: T. Burris-Mog, K. Harres, F. Nurnberg, S. Busold, M. Bussmann et al.
Using a pulse power solenoid, we demonstrate efficient capture of laser accelerated proton beams and the ability to control their large divergence angles and broad energy range. Simulations using measured data for the input parameters give inference into the phase-space and transport efficiencies of ... [Phys. Rev. ST Accel. Beams 14, 121301 ] published .
Harmonic radiation of a relativistic nonlinear inverse Compton scattering using two laser wavelengths: Y. Sakai, O. Williams, G. Andonian, A. Fukasawa, E. Hemsing et al.
The use of two different wavelength lasers in the nonlinear regime of the inverse Compton scattering interaction is proposed in order to provide a new strategy for controlling scattered photon energy distributions in the x-ray to gamma-ray spectral region. In this nonlinear interaction, the componen ... [Phys. Rev. ST Accel. Beams 14, 120702 ] published .
Tunable Radiation Source by Coupling Laser-Plasma-Generated Electrons to a Periodic Structure: Z. Jin (金展), Z. L. Chen (陈正林), H. B. Zhuo (卓红斌), A. Kon (今亮), M. Nakatsutsumi (中堤基彰) et al.
Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the ... [Phys. Rev. Lett. 107, 265003 ] published .
Laser Shaping of a Relativistic Intense, Short Gaussian Pulse by a Plasma Lens: H. Y. Wang, C. Lin, Z. M. Sheng, B. Liu, S. Zhao et al.
By 3D particle-in-cell simulation and analysis, we propose a plasma lens to make high intensity, high contrast laser pulses with a steep front. When an intense, short Gaussian laser pulse of circular polarization propagates in near-critical plasma, it drives strong currents of relativistic electrons ... [Phys. Rev. Lett. 107, 265002 ] published .
Symmetry breaking from radiation reaction in ultra-intense laser fields: Chris Harvey, Thomas Heinzl, and Mattias Marklund
We discuss radiation reaction effects on charges propagating in ultraintense laser fields. Our analysis is based on an analytic solution of the Landau-Lifshitz equation. We suggest quantifying radiation reaction in terms of a symmetry breaking parameter associated with the violation of null translat ... [Phys. Rev. D 84, 116005 ] published .
Radiative polarization of electrons in a strong laser wave: Dmitry V. Karlovets
We reanalyze the problem of radiative polarization of electrons brought into collision with a circularly polarized strong plane wave. We present an independent analytical verification of formulas for the cross section given by Ivanov et al. [Eur. Phys. J. C 36, 127 (2004)]. By choosing the exact ele ... [Phys. Rev. A 84, 062116 ] published .
Comparison of the electron density measurements using Thomson scattering and emission spectroscopy for laser induced breakdown in one atmosphere of helium: E. Nedanovska, G. Nersisyan, T. J. Morgan, L. Huwel, C. L. S. Lewis et al.
Thomson scattering from laser-induced plasma in atmospheric helium was used to obtain temporally and spatially resolved electron temperature and density profiles. Electron density measurements at 5 [mu]s after breakdown are compared with those derived from the separation of the allowed and forbidden ... [Appl. Phys. Lett. 99, 261504 (2011)] published Wed Dec 28, 2011.
Intense terahertz emission from atomic cluster plasma produced by intense femtosecond laser pulses: Fazel Jahangiri, Masaki Hashida, Takeshi Nagashima, Shigeki Tokita, Masanori Hangyo et al.
Terahertz (THz) emission from argon cluster plasma, generated by intense femtosecond laser pulses in the energy range of 1070 mJ, has been investigated. THz polarization, energy dependence, and angular distribution were measured to provide an initial discussion on the mechanisms of THz emission. THz ... [Appl. Phys. Lett. 99, 261503 (2011)] published Wed Dec 28, 2011.
Laser guiding plasma channel formation criterion in highly relativistic regime: Y. J. Gu, Z. Zhu, Q. Kong, Y. Y. Li, X. F. Li et al.
Self-formed plasma channels induced by ultra-intense and ultra-short laser pulses have been investigated with 2.5-dimensional particle-in-cell simulations. A criterion of channel formation under the highly relativistic regime is proposed and tested by simulation results. Good matches between criteri ... [Appl. Phys. Lett. 99, 241501 (2011)] published Wed Dec 14, 2011.
Effect of air breakdown with a focusing lens on ultrashort laser ablation: Wenqian Hu, Yung C. Shin, and Galen King
The effect of air breakdown on ultrashort laser ablation is investigated in this letter using an integrated simulation method on atomistic level. The generation of air breakdown with different laser peak power densities in the range from 10 to 10 W/cm and various focusing conditions is analyzed. Air ... [Appl. Phys. Lett. 99, 234104 (2011)] published Tue Dec 6, 2011.
Dynamic behavior of postfilamentation Raman pulses: Jean-Francois Daigle, Tie-Jun Wang, Sima Hosseini, Shuai Yuan, Gilles Roy et al.
We report on the postfilamentation behavior of a Stokes pulse created from intense and collimated ultrashort pulses propagating in air. A systematic analysis of the pulse propagation revealed that the redshifted Raman pulse produced during filamentation had a larger divergence than the postfilamenta ... [Appl. Opt. 50, 6234 (2011)] published Wed Dec 7, 2011.
Ultrafast laser ablation of gold thin film targets: S. Amoruso, N. N. Nedyalkov, X. Wang, G. Ausanio, R. Bruzzese et al.
Ultrafast laser ablation of a gold thin film is studied and compared with that of a bulk target, with particular emphasis given to the process of nanoparticles generation. The process is carried out in a condition where a single laser shot removes all the irradiated film spot. The experimental resul ... [J. Appl. Phys. 110, 124303 (2011)] published Mon Dec 19, 2011.
Femtosecond laser tuning of silicon microring resonators: Daniel Bachman, Zhijiang Chen, Ashok M. Prabhu, Robert Fedosejevs, Ying Y. Tsui et al.
Femtosecond laser modification is demonstrated as a possible method for postfabrication tuning of silicon microring resonators. Single 400 nm femtosecond laser pulses were used to modify the effective index of crystalline silicon microring waveguides by either amorphization or surface nanomilling de ... [Opt. Lett. 36, 4695 (2011)] published Mon Dec 5, 2011.
Full-band quantum-dynamical theory of saturation and four-wave mixing in graphene: Zheshen Zhang and Paul L. Voss
The linear and nonlinear optical response of graphene are studied within a quantum-mechanical, full-band, steady-state density-matrix model. This nonpurtabative method predicts the saturatable absorption and saturable four-wave mixing of graphene. The model includes tau and tau time constants that d ... [Opt. Lett. 36, 4569 (2011)] published Mon Dec 5, 2011.
Strain field manipulation in ultrafast laser inscribed BiBO optical waveguides for nonlinear applications: S. J. Beecher, R. R. Thomson, D. T. Reid, N. D. Psaila, M. Ebrahim-Zadeh et al.
A novel technique was used to control the spatial overlap of the orthogonal linearly polarized waveguide modes in ultrafast laser inscribed BiBO waveguides. We report that the strain fields induced by the expansion of material in the laser focus can be considered independently in the design of type ... [Opt. Lett. 36, 4548 (2011)] published Mon Dec 5, 2011.
Impact of dispersion profiles of silicon waveguides on optical parametric amplification in the femtosecond regime: Zhaolu Wang, Hongjun Liu, Nan Huang, Qibing Sun, and Jin Wen
The impact of dispersion profiles of silicon waveguides on femtosecond optical parametric amplification (OPA) is theoretically investigated. It is found that flat quasi-phase-matching, smooth temporal profiles and separable spectra for 200 fs pulses can be obtained by tailoring the cross-section of ... [Opt. Express 19, 24730 (2011)] published Thu Dec 1, 2011.
10Gbit/s all-optical NRZ-OOK to RZ-OOK format conversion in an ultra-small III-V-on-silicon microdisk fabricated in a CMOS pilot line: Rajesh Kumar, Thijs Spuesens, Pauline Mechet, Nicolas Olivier, Jean-Marc Fedeli et al.
We report the demonstration of an all-optical, bias free and error-free (bit-error-rate ~10), 10Gbit/s non-return-to-zero (NRZ) to return-to-zero (RZ) data format conversion using a 7.5[mu]m diameter III-V-on-silicon microdisk resonator. The device is completely processed in a 200mm CMOS pilot line. ... [Opt. Express 19, 24647 (2011)] published Thu Dec 1, 2011.
Ultrafast all-optical switching in a silicon-based plasmonic nanoring resonator: S. Sederberg, D. Driedger, M. Nielsen, and A.Y. Elezzabi
A silicon-based plasmonic nanoring resonator is proposed for ultrafast, all-optical switching applications. Full-wave numerical simulations demonstrate that the photogeneration of free carriers enables ultrafast switching of the device by shifting the transmission minimum of the resonator with a swi ... [Opt. Express 19, 23494 (2011)] published Thu Dec 1, 2011.
Extremely nondegenerate two-photon absorption in direct-gap semiconductors [Invited]: Claudiu M. Cirloganu, Lazaro A. Padilha, Dmitry A. Fishman, Scott Webster, David J. Hagan et al.
Two-photon absorption (2PA) spectra with pairs of extremely nondegenerate photons are measured in several direct-gap semiconductors (GaAs, CdTe, ZnO, ZnS and ZnSe) using picosecond or femtosecond pulses. In ZnSe, using photons with a ratio of energies of ~12, we obtain a 270-fold enhancement of 2PA ... [Opt. Express 19, 22951 (2011)] published Thu Dec 1, 2011.
Reducing multi-photon rates in pulsed down-conversion by temporal multiplexing: M. A. Broome, M. P. Almeida, A. Fedrizzi, and A. G. White
We present a simple technique to reduce the emission rate of higher-order photon events from pulsed spontaneous parametric down-conversion. The technique uses extra-cavity control over a mode locked ultrafast laser to simultaneously increase repetition rate and reduce the energy of each pulse from t ... [Opt. Express 19, 22698 (2011)] published Thu Dec 1, 2011.
Laser mode feeding by shaking quantum dots in a planar microcavity: C. Brggemann, A. V. Akimov, A. V. Scherbakov, M. Bombeck, C. Schneider et al.
Semiconductor light emission can be changed considerably in an optical resonator. Prerequisite is that the electronic transitions involved in light generation are in resonance with a cavity mode. Although resonance can be arranged through dedicated fabrication, there are cases where this is virtuall ... [Nat. Photonics 6, 30 (2011)] published Thu Dec 22, 2011.
Bistability and instability of dark-antidark solitons in the cubic-quintic nonlinear Schrodinger equation: M. Crosta, A. Fratalocchi, and S. Trillo
We characterize the full family of soliton solutions sitting over a background plane wave and ruled by the cubic-quintic nonlinear Schrodinger equation in the regime where a quintic focusing term represents a saturation of the cubic defocusing nonlinearity. We discuss the existence and properties of ... [Phys. Rev. A 84, 063809 ] published .
Supercontinuum Generation with Femtosecond Self-Healing Airy Pulses: Craig Ament, Pavel Polynkin, and Jerome V. Moloney
We report experiments and numerical simulations on supercontinuum generation with femtosecond Airy pulses in a highly nonlinear optical fiber. The ability of the Airy waveform to regenerate its dominant intensity peak results in the generation of distinct spectral features. Airy pulses and other sel ... [Phys. Rev. Lett. 107, 243901 ] published .
Terahertz generation from laser filaments in the presence of a static electric field in a plasma: Lalita Bhasin and V. K. Tripathi
Two femtosecond laser pulses with frequencies omega and omega that undergo filamentation in a plasma couple nonlinearly in the presence of a transverse, static electric field to generate terahertz wave at the frequency omega-omega. The coupling is enhanced in the presence of the static electric fiel ... [Phys. Plasmas 18, 123106 (2011)] published Thu Dec 29, 2011.
Higher-Order Modulation Instability in Nonlinear Fiber Optics: Miro Erkintalo, Kamal Hammani, Bertrand Kibler, Christophe Finot, Nail Akhmediev et al.
We report theoretical, numerical, and experimental studies of higher-order modulation instability in the focusing nonlinear Schrodinger equation. This higher-order instability arises from the nonlinear superposition of elementary instabilities, associated with initial single breather evolution follo ... [Phys. Rev. Lett. 107, 253901 ] published .
Two-photon indirect optical injection and two-color coherent control in bulk silicon: J. L. Cheng, J. Rioux, and J. E. Sipe
Using an empirical pseudopotential description of electron states and an adiabatic bond charge model for phonon states in bulk silicon, we theoretically investigate two-photon indirect optical injection of carriers and spins and two-color coherent control of the motion of the injected carriers and s ... [Phys. Rev. B 84, 235204 ] published .
Effect of wave-function localization on the time delay in photoemission from surfaces: C.-H. Zhang and U. Thumm
We investigate streaking time delays in the photoemission from a solid model surface as a function of the degree of localization of the initial-state wave functions. We consider a one-dimensional slab with lattice constant a of attractive Gaussian-shaped core potentials of width sigma. The parameter ... [Phys. Rev. A 84, 065403 ] published .
Nonponderomotive electron acceleration in ultrashort surface-plasmon fields: Peter Racz and Peter Dombi
We investigate the nonponderomotive nature of ultrafast plasmonic electron acceleration in strongly decaying electromagnetic fields generated by few-cycle and single-cycle femtosecond laser pulses. We clearly identify the conditions contributing to nonponderomotive acceleration and establish fundame ... [Phys. Rev. A 84, 063844 ] published .
Quantum complementarity of cavity photons coupled to a three-level system: R. Vilardi, A. Ridolfo, S. Portolan, S. Savasta, and O. Di Stefano
Recently a device enabling the ultrafast all-optical control of the wave-particle duality of light was proposed [Ridolfo et al., Phys. Rev. Lett. 106, 013601 (2011)]. It is constituted by a three-level quantum emitter strongly coupled to a microcavity and can be realized by exploiting a great variet ... [Phys. Rev. A 84, 063842 ] published .
Broadband colored-crescent generation in a single beta-barium-borate crystal by intense femtosecond pulses: L. Wang, Y. X. Fan, H. Zhu, Z. D. Yan, H. Zeng et al.
A visible colored crescent with a bandwidth broader than 220 nm is observed experimentally by loosely focused femtosecond pulses in a bulk quadratic nonlinear crystal (beta-BBO crystal) at certain incident angles. Through the analysis based on a simple collinear phase-matching model, we suggest that ... [Phys. Rev. A 84, 063831 ] published .
Chirped femtosecond solitons and double-kink solitons in the cubic-quintic nonlinear Schrodinger equation with self-steepening and self-frequency shift: Alka, Amit Goyal, Rama Gupta, C. N. Kumar, and Thokala Soloman Raju
We demonstrate that the competing cubic-quintic nonlinearity induces propagating solitonlike dark(bright) solitons and double-kink solitons in the nonlinear Schrodinger equation with self-steepening and self-frequency shift. Parameter domains are delineated in which these optical solitons exist. Als ... [Phys. Rev. A 84, 063830 ] published .
Conservation of the photon number in the generalized nonlinear Schrodinger equation in axially varying optical fibers: O. Vanvincq, J. C. Travers, and A. Kudlinski
We reexamine the derivation of the generalized nonlinear Schrodinger equation in the case of nonaxially uniform optical fibers, taking into account the longitudinal and spectral evolutions of all pertinent linear parameters. Our theory leads to an improved form of this equation that highlights an ad ... [Phys. Rev. A 84, 063820 ] published .
Enhancement of peak intensity in a filament core with spatiotemporally focused femtosecond laser pulses: Bin Zeng, Wei Chu, Hui Gao, Weiwei Liu, Guihua Li et al.
We demonstrate that the peak intensity in the filament core, which is inherently limited by the intensity clamping effect during femtosecond laser filamentation, can be significantly enhanced using spatiotemporally focused femtosecond laser pulses. In addition, the filament length obtained by spatio ... [Phys. Rev. A 84, 063819 ] published .
Time-resolved femtosecond optical characterization of multi-photon absorption in high-pressure-grown AlGaN single crystals: Jie Zhang, Andrey Belousov, Janusz Karpinski, Bertram Batlogg, Gary Wicks et al.
We report our experimental studies on time-resolved pumpprobe spectroscopy in high-quality AlGaN single crystals, grown using a solution technique in a high-nitrogen-gas-pressure system. Our optical measurements were performed using a non-traditional, two-beam [one ultraviolet (UV) and one infrared ... [J. Appl. Phys. 110, 113112 (2011)] published Mon Dec 12, 2011.
Ultrafast two-bit all-optical analog-to-digital conversion based on femtosecond soliton sequence sampling: Aida Esmaeilian-Marnani, Ahmad Fauzi Abas, Mohd Adzir Mahdi, and Khairulmizam Samsudin
Realization of two-bit all-optical analog-to-digital conversion for an analog signal sampled by a femtosecond soliton sequence is investigated. Two approaches are suggested. The first one is based on filtering the broadened soliton spectrum after evolution over half of the soliton period in a standa ... [Opt. Eng. 50, 125001 (2011)] published Thu Nov 17, 2011.
Photoluminescence and ultrafast intersubband relaxation in Ge/SiGe multiple quantum wells: E. Gatti, E. Grilli, M. Guzzi, D. Chrastina, G. Isella et al.
The intricate relaxation dynamics in compressively strained Ge quantum wells with Ge-rich SiGe barriers is investigated systematically for various excitation conditions. Evidence of efficient ultrafast intersubband relaxation in competition with the intrasubband electron cooling is found in continuo ... [Phys. Rev. B 84, 245319 ] published .
Quantum control of a Landau-quantized two-dimensional electron gas in a GaAs quantum well using coherent terahertz pulses: T. Arikawa, X. Wang, D. J. Hilton, J. L. Reno, W. Pan et al.
We demonstrate coherent control of cyclotron resonance in a two-dimensional electron gas (2DEG). We use a sequence of terahertz (THz) pulses to control the amplitude of coherent cyclotron resonance oscillations in an arbitrary fashion via phase-dependent coherent interactions. We observe a self-inte ... [Phys. Rev. B 84, 241307 ] published .
Sub-100 fs charge transfer in a novel donoracceptordonor triad organized in a smectic film: T. Roland, J. Leonard, G. Hernandez Ramirez, S. Mery, O. Yurchenko et al.
Ultrafast transient absorption spectroscopy is performed on a novel donoracceptordonor triad made of two identical bisthiophene derivatives as electron donors and a central perylenediimide moiety as electron acceptor. The triad is extended at both ends by covalently bound siloxane chains that confer ... [Phys. Chem. Chem. Phys. 14, 273 (2011)] published Mon Dec 5, 2011.
Observing the Multiexciton State in Singlet Fission and Ensuing Ultrafast Multielectron Transfer: Wai-Lun Chan, Manuel Ligges, Askat Jailaubekov, Loren Kaake, Luis Miaja-Avila et al.
Multiple exciton generation (MEG) refers to the creation of two or more electron-hole pairs from the absorption of one photon. Although MEG holds great promise, it has proven challenging to implement, and questions remain about the underlying photo-physical dynamics in nanocrystalline as well as mol ... [Science 334, 1541 (2011)] published Wed Dec 14, 2011.
Ultrafast electrical measurements of polarization dynamics in ferroelectric thin-film capacitors: Alexei Grigoriev, Mandana Meisami Azad, and John McCampbell
We have developed a new approach to measure fast electrical signals during polarization switching in ferroelectric thin-film capacitors. This article describes a simple method for probing transient currents and voltages in a broad range of time scales from microseconds to hundreds of picoseconds. In ... [Rev. Sci. Instrum. 82, 124704 (2011)] published Wed Dec 14, 2011.
Ultrafast energy transfer of one-dimensional excitons between carbon nanotubes: a femtosecond time-resolved luminescence study: Takeshi Koyama, Yasumitsu Miyata, Koji Asaka, Hisanori Shinohara, Yahachi Saito et al.
Excitation energy transfer has long been an intriguing subject in the fields of photoscience and materials science. Along with the recent progress of photovoltaics, photocatalysis, and photosensors using nanoscale materials, excitation energy transfer between a donor and an acceptor at a short dista ... [Phys. Chem. Chem. Phys. 14, 1070 (2011)] published Fri Dec 16, 2011.
Characteristics of laser absorption and welding in FOTURAN glass by ultrashort laser pulses: Isamu Miyamoto, Kristian Cvecek, Yasuhiro Okamoto, Michael Schmidt, and Henry Helvajian
The nonlinear absorptivity of FOTURAN glass to ultrashort laser pulses is evaluated by experimental measurement and thermal conduction model at different parameters including energy and repetition rate of the laser pulse, translation speed and thermal properties of the sample. The mechanical strengt ... [Opt. Express 19, 22961 (2011)] published Thu Dec 1, 2011.
Characterization of Femtosecond laser-irradiation crystallization and structure of multiple periodic Si/SbTe nanocomposite films by coherent phonon spectroscopy: Weiling Zhu, Changzhou Wang, Mingcheng Sun, Simian Li, Jiwei Zhai et al.
Multiple parameters of nanocomposite Si/SbTe multilayer films are possibly optimized simultaneously to satisfy the development of ideal phase-change memory devices by adjusting chemical composition and physical structure of multilayer films. The crystallization and structure of the films are studied ... [Opt. Express 19, 22684 (2011)] published Thu Dec 1, 2011.
Driving force of ultrafast magnetization dynamics: B Mueller, T Roth, M Cinchetti, M Aeschlimann, and B Rethfeld
Irradiating a ferromagnetic material with an ultrashort laser pulse leads to demagnetization on the femtosecond timescale. We implement ElliottYafet-type spin-flip scattering, mediated by electronelectron and electronphonon collisions, in the framework of a spin-resolved Boltzmann equation. Consider ... [New J. Phys. 13, 123010 (2011)] published Thu Dec 29, 2011.
Coherent control of three-spin states in a triple quantum dot: L. Gaudreau, G. Granger, A. Kam, G. C. Aers, S. A. Studenikin et al.
Spin qubits involving individual spins in single quantum dots or coupled spins in double quantum dots have emerged as potential building blocks for quantum information processing applications. It has been suggested that triple quantum dots may provide additional tools and functionalities. These inc ... [Nature Phys. 8, 54 (2011)] published Thu Dec 22, 2011.
Induction of coherent magnetization switching in a few atomic layers of FeCo using voltage pulses: Yoichi Shiota, Takayuki Nozaki, Frdric Bonell, Shinichi Murakami, Teruya Shinjo et al.
The magnetization direction of a metallic magnet has generally been controlled by a magnetic field or by spin-current injection into nanosized magnetic cells. Both these methods use an electric current to control the magnetization direction; therefore, they are energy consuming. Magnetization contr ... [Nature Mater. 11, 39 (2011)] published Thu Dec 15, 2011.
Ultrafast Transparent Ceramic Scintillators Using the Yb Charge Transfer Luminescence in REO Host: Takayuki Yanagida, Yutaka Fujimoto, Shunsuke Kurosawa, Kenichi Watanabe, Hideki Yagi et al.
We report a new discovery of Yb-doped ultrafast scintillators based on the Yb charge transfer luminescence. Transparent ceramic Yb-doped YO, ScO, LuO, and YbO were prepared by sintering. When irradiated by \gamma- and X-rays, they showed a well detectable photoabsorption peak in the pulse height spe ... [Appl. Phys. Express 4, 126402 (2011)] published Tue Dec 13, 2011.
Superior local conductivity in self-organized nanodots on indium-tin-oxide films induced by femtosecond laser pulses: Chih Wang, Hsuan-I Wang, Wei-Tsung Tang, Chih-Wei Luo, Takayoshi Kobayashi et al.
Large-area surface ripple structures of indium-tin-oxide films, composed of self-organized nanodots, were induced by femtosecond laser pulses, without scanning. The multi-periodic spacing (?800 nm, ?400 nm and ?200 nm) was observed in the laser-induced ripple of ITO films. The local conductivity of ... [Opt. Express 19, 24286 (2011)] published Thu Dec 1, 2011.
Electric field-induced coherent control in GaAs: polarization dependence and electrical measurement [Invited]: J. K. Wahlstrand, H. Zhang, S. B. Choi, J. E. Sipe, and S. T. Cundiff
A static electric field enables coherent control of the photoexcited carrier density in a semiconductor through the interference of one- and two-photon absorption. An experiment using optical detection is described. The polarization dependence of the signal is consistent with a calculation using a 1 ... [Opt. Express 19, 22563 (2011)] published Thu Dec 1, 2011.
Harmonic generation and energy transport in dielectric and semiconductors at visible and UV wavelengths: the case of GaP: V. Roppo, N. Akozbek, D. de Ceglia, M. A. Vincenti, and M. Scalora
We study the propagation and momentum transport of the inhomogeneous component of second and third harmonic pulses in dielectrics and semiconductors, at visible and UV wavelengths, focusing on materials like GaP. In these spectral regions GaP is characterized by large absorption, metallic behavior o ... [J. Opt. Soc. Am. B 28, 2888 (2011)] published Fri Dec 23, 2011.
Ultrafast recombination for NiO sensitized with a series of perylene imide sensitizers exhibiting Marcus normal behaviour: Amanda L. Smeigh, Loic Le Pleux, Jerome Fortage, Yann Pellegrin, Errol Blart et al.
Ultrafast recombination observed from several perylene imide sensitizers bound to NiO appears to align with Marcus normal region behaviour; this indicates recombination to intra-bandgap states. ... [Chem. Commun. 48, 678 (2011)] published Mon Dec 12, 2011.
Enhanced rectifying response from metal-insulator-insulator-metal junctions: P. Maraghechi, A. Foroughi-Abari, K. Cadien, and A. Y. Elezzabi
We present on a metal-insulator-insulator-metal quantum electronic tunneling devices suitable for high speed rectifiers. Through the introduction of double oxide layer between similar metallic electrodes, a cascaded potential barrier is formed which alters the electron tunneling mechanism at forward ... [Appl. Phys. Lett. 99, 253503 (2011)] published Tue Dec 20, 2011.
Unraveling the Solid-Liquid-Vapor Phase Transition Dynamics at the Atomic Level with Ultrafast X-Ray Absorption Near-Edge Spectroscopy: F. Dorchies, A. Levy, C. Goyon, P. Combis, D. Descamps et al.
X-ray absorption near-edge spectroscopy (XANES) is a powerful probe of electronic and atomic structures in various media, ranging from molecules to condensed matter. We show how ultrafast time resolution opens new possibilities to investigate highly nonequilibrium states of matter including phase tr ... [Phys. Rev. Lett. 107, 245006 ] published .
Hole spin relaxation and intervalley electron scattering in germanium: Eric J. Loren, J. Rioux, C. Lange, J. E. Sipe, H. M. van Driel et al.
Hole spin relaxation and intervalley electron scattering in bulk Ge at 300 K are distinguished and selectively investigated using a spectrally, temporally, and polarization-resolved pump-probe differential transmission technique that takes advantage of the indirect band gap nature of Ge and of the d ... [Phys. Rev. B 84, 214307 ] published .
Theory of the inverse Faraday effect in view of ultrafast magnetization experiments: Daria Popova, Andreas Bringer, and Stefan Blugel
We supplement the theory of the inverse Faraday effect, which was developed in the 1960s, to the conditions used today in ultrafast magnetization experiments. We show that assumptions used to derive the effective Hamiltonian and magnetization are not valid under these conditions. We extended the app ... [Phys. Rev. B 84, 214421 ] published .
Linear and nonlinear Fano resonance on two-dimensional magnetic metamaterials: H. Liu, G. X. Li, K. F. Li, S. M. Chen, S. N. Zhu et al.
We demonstrate that both linear and nonlinear Fano resonances can be realized on two dimensional magnetic metamaterials. The Fano resonance comes from the interference between localized magnetic plasmon resonance and propagating surface plasmon polaritons. When studying the linear optical response o ... [Phys. Rev. B 84, 235437 ] published .
Publisher's Note: Observation of Size-Dependent Thermalization in CdSe Nanocrystals Using Time-Resolved Photoluminescence Spectroscopy [Phys. Rev. Lett. 107, 177403 (2011)]: Daniel C. Hannah, Nicholas J. Dunn, Sandrine Ithurria, Dmitri V. Talapin, Lin X. Chen et al.
Abstract not available. [Phys. Rev. Lett. 107, 259901 ] published .
Nonlinear optical properties of lanthanum-modified lead zirconate titanate investigated by the femtosecond Z-scan technique: Tsong-Ru Tsai and Chih-Hsiung Yu
We used a closed-aperture Z-scan technique to study the nonlinear optical refractive index of lanthanum-modified lead zirconate titanate (PLZT) (9/65/35) ceramics. Our laser light source was a mode-locked titanium-sapphire laser, the output pulse width was approximately 100 femtoseconds at a wavelen ... [Appl. Phys. Lett. 99, 241101 (2011)] published Mon Dec 12, 2011.
Imaging of surface plasmon polariton fields excited at a nanometer-scale slit: Lingxiao Zhang, Atsushi Kubo, Leiming Wang, Hrvoje Petek, and Tamar Seideman
Nonlinear two-photon photoemission electron microscopy is used to image surface plasmon polariton (SPP) wave packets excited by an obliquely incident laser pulse (~10 fs) at a single slit fabricated in a thin silver film. We image the forward propagating polarization grating formed by the coherent s ... [Phys. Rev. B 84, 245442 ] published .
Temperature-insensitive optical alignment of the exciton in nanowire-embedded GaN quantum dots: A. Balocchi, J. Renard, C. T. Nguyen, B. Gayral, T. Amand et al.
We report on the exciton spin dynamics of nanowire-embedded GaN/AlN quantum dots (QDs) investigated by time-resolved photoluminescence spectroscopy. Under a linearly polarized quasiresonant excitation, we evidence the quenching of the exciton spin relaxation and a temperature-insensitive degree of t ... [Phys. Rev. B 84, 235310 ] published .
Direct observation of two-phonon bound states in ZnTe: Jianbo Hu, Oleg V. Misochko, and Kazutaka G. Nakamura
A coherent two-phonon bound state has been impulsively generated in ZnTe(110) via second-order Raman scattering in the time domain. The two-phonon bound state, composed of two acoustic phonons anticorrelated in a wave vector, exhibits full Gamma symmetry and has energy higher than the corresponding ... [Phys. Rev. B 84, 224304 ] published .
Ultrashort-pulse laser ablation of nanocrystalline aluminum: Maxime Gill-Comeau and Laurent J. Lewis
Molecular-dynamics simulations of the ablation of nanocrystalline Al films by ultrashort laser pulses in the low-fluence (no-ionization) regime (02.5 times the ablation threshold, F) are reported. The simulations employ an embedded-atom method potential for the dynamics of the ions and a realistic t ... [Phys. Rev. B 84, 224110 ] published .
Dynamics of photoinduced phenomena in AVO (A = Ba, Sr): A. Nogami, K. Takubo, T. Kajita, M. Hoshino, and T. Katsufuji
We studied the dynamics of photoinduced phenomena in AVO (A = Ba, Sr), where the ground state changes from an insulating state with V trimerization (Ba) to another insulating state with no structural anomaly (Sr). We found that the time dependence of photoinduced reflectivity change is similar up to ... [Phys. Rev. B 84, 214442 ] published .
Influence of temperature on dynamics of birefringence switching in photochromic nematic phase: Jaroslaw Mysliwiec, Maciej Czajkowski, Stanislaw Bartkiewicz, Krystian Zygadlo, Zbigniew Galewski et al.
We present results of dynamic and fast switching of birefringence in a photochromic liquid-crystalline system as a function of the sample temperature. The system consists of photochromic molecules of 4-heptyl-4[prime]-methoxyazobenzene showing a liquid-crystalline nematic state close to room tempera ... [J. Appl. Phys. 110, 113104 (2011)] published Mon Dec 5, 2011.
Evidence for Confined Tamm Plasmon Modes under Metallic Microdisks and Application to the Control of Spontaneous Optical Emission: O. Gazzano, S. Michaelis de Vasconcellos, K. Gauthron, C. Symonds, J. Bloch et al.
We demonstrate strong confinement of the optical field by depositing a micron sized metallic disk on a planar distributed Bragg reflector. Confined Tamm plasmon modes are evidenced both experimentally and theoretically, with a lateral confinement limited to the disk area and strong coupling to TE po ... [Phys. Rev. Lett. 107, 247402 ] published .
Coherent Longitudinal-Optical Ground-State Phonon in CdSe Quantum Dots Triggered by Ultrafast Charge Migration: L. Dworak, V. V. Matylitsky, M. Braun, and J. Wachtveitl
We observe the CdSe longitudinal-optical ground-state phonon in the electron transfer system composed of CdSe quantum dots and methylviologen directly by femtosecond absorption spectroscopy. A significant phase shift indicates that the coherent oscillations are triggered by an ultrafast charge migra ... [Phys. Rev. Lett. 107, 247401 ] published .
Synthesis of submicron metastable phase of silicon using femtosecond laser-driven shock wave: Masashi Tsujino (辻野雅之), Tomokazu Sano (佐野智一), Osami Sakata (坂田修身), Norimasa Ozaki (尾崎典雅), Shigeru Kimura (木村滋) et al.
We measured the grain size of metastable phase of Si synthesized by shock compression. We analyzed the crystalline structures of the femtosecond laser-driven shock compressed silicon with x-ray diffraction measurements. We found that submicron grains of metastable Si-VIII exist in the silicon. We su ... [J. Appl. Phys. 110, 126103 (2011)] published Thu Dec 29, 2011.
Optical properties and thermal response of copper films induced by ultrashort-pulsed lasers: Yunpeng Ren, J. K. Chen, and Yuwen Zhang
A critical point model with three Lorentzian terms for interband transition was proposed to describe temperature-dependent reflectivity (R) and absorption coefficient (alpha) for copper irradiated by ultrashort-pulsed lasers of wavelength 2001000 nm. After validated with experimental data at room te ... [J. Appl. Phys. 110, 113102 (2011)] published Thu Dec 1, 2011.
Carrier dynamics and activation energy of CdTe quantum dots in a CdZnTe quantum well: W. I. Han, J. H. Lee, J. S. Yu, J. C. Choi, and H. S. Lee
We investigate the optical properties of CdTe quantum dots (QDs) in a CdZnTe quantum well (QW) grown on GaAs (100) substrates. Carrier dynamics of CdTe/ZnTe QDs and quantum dots-in-a-well (DWELL) structure is studied using time-resolved photoluminescence (PL) measurements, which show the longer exci ... [Appl. Phys. Lett. 99, 231908 (2011)] published Thu Dec 8, 2011.
Energy relaxation of intermolecular motions in supercooled water and ice: A molecular dynamics study: Takuma Yagasaki and Shinji Saito
We investigate the energy relaxation of intermolecular motions in liquid water at temperatures ranging from 220 K to 300 K and in ice at 220 K using molecular dynamics simulations. We employ the recently developed frequency resolved transient kinetic energy analysis, which provides detailed informat ... [J. Chem. Phys. 135, 244511 (2011)] published Thu Dec 29, 2011.
High-Field Transport in an Electron-Hole Plasma: Transition from Ballistic to Drift Motion: P. Bowlan, W. Kuehn, K. Reimann, M. Woerner, T. Elsaesser et al.
The time evolution of high-field carrier transport in bulk GaAs is studied with intense femtosecond THz pulses. While ballistic transport of electrons occurs in an n-type sample, a transition from ballistic to driftlike motion is observed in an electron-hole plasma. This onset of friction is due to ... [Phys. Rev. Lett. 107, 256602 ] published .
Non-Markovian effects in time-resolved fluorescence spectrum of molecular aggregates: Tracing polaron formation: Andrius Gelzinis, Darius Abramavicius, and Leonas Valkunas
Time-resolved fluorescence spectroscopy of molecular aggregates is described using the response function theory, which incorporates exciton dynamics through nonequilibrium Green's functions. The dynamics are simulated using nonperturbative density matrix theory, which allows us to describe spectral ... [Phys. Rev. B 84, 245430 ] published .
Shot noise and conductivity at high bias in bilayer graphene: Signatures of electron-optical phonon coupling: A. Fay, R. Danneau, J. K. Viljas, F. Wu, M. Y. Tomi et al.
We have studied electronic conductivity and shot noise of bilayer graphene (BLG) sheets at high bias voltages and low bath temperature T=4.2 K. As a function of bias, we find initially an increase of the differential conductivity, which we attribute to self-heating. At higher bias, the conductivity ... [Phys. Rev. B 84, 245427 ] published .
Quantum-beat spectroscopy of image-potential resonances: M. Marks, C. H. Schwalb, K. Schubert, J. Gudde, and U. Hofer
The dynamics of electrons in image-potential resonances on the Ag(111) surface, i.e., image-potential states that are resonant with bulk bands, have been studied by time-resolved two-photon photoemission in combination with quantum-beat spectroscopy. Energies and lifetimes of these resonances were d ... [Phys. Rev. B 84, 245402 ] published .
Real-time approach to the optical properties of solids and nanostructures: Time-dependent Bethe-Salpeter equation: C. Attaccalite, M. Gruning, and A. Marini
Many-body effects are known to play a crucial role in the electronic and optical properties of solids and nanostructures. Nevertheless, the majority of theoretical and numerical approaches able to capture the influence of Coulomb correlations are restricted to the linear response regime. In this wor ... [Phys. Rev. B 84, 245110 ] published .
Driving magnetic order in a manganite by ultrafast lattice excitation: M. Forst, R. I. Tobey, S. Wall, H. Bromberger, V. Khanna et al.
Femtosecond midinfrared pulses are used to directly excite the lattice of the single-layer manganite LaSrMnO. Magnetic and orbital orders, as measured by femtosecond resonant soft x-ray diffraction with an x-ray free-electron laser, are reduced within a few picoseconds. This effect is interpreted as ... [Phys. Rev. B 84, 241104 ] published .
Ultrafast relaxation of highly excited hot electrons in Si: Roles of the LX intervalley scattering: T. Ichibayashi, S. Tanaka, J. Kanasaki, K. Tanimura, and Thomas Fauster
Two-photon photoemission (2PPE) spectroscopy is used to reveal dynamic relaxation of highly excited electrons generated by 3 eV photons in Si. Monochromatic 2PPE at probe-photon energies ranging from 3.2 to 3.5 eV reveals a coherent 2PPE peak from the valence band maximum, and a transiently populate ... [Phys. Rev. B 84, 235210 ] published .
Allowed and forbidden Raman scattering mechanisms for detection of coherent LO phonon and plasmon-coupled modes in GaAs: Kunie Ishioka, Amlan Kumar Basak, and Hrvoje Petek
Detection mechanisms of coherent phonons in variously doped GaAs are investigated by transient reflectivity method with photoexcitation near the E gap and probe near either the E or E gaps. By varying the probe light polarization angle, the coherent amplitudes of both the LO phonon and the LO phonon ... [Phys. Rev. B 84, 235202 ] published .
All-optical magnetization recording by tailoring optical excitation parameters: Daniel Steil, Sabine Alebrand, Alexander Hassdenteufel, Mirko Cinchetti, and Martin Aeschlimann
We investigate the dependency of all-optical magnetization switching on the properties of the exciting laser pulse by specifically tailoring all accessible laser parameterspulse duration, wavelength, chirp, and bandwidthover a wide range. Our results show that all-optical switching can be achieved w ... [Phys. Rev. B 84, 224408 ] published .
Electron-phonon scattering dynamics in ferromagnetic metals and their influence on ultrafast demagnetization processes: Sven Essert and Hans Christian Schneider
We theoretically investigate spin-dependent carrier dynamics due to the electron-phonon interaction after ultrafast optical excitation in ferromagnetic metals. We calculate the electron-phonon matrix elements including the spin-orbit interaction in the electronic wave functions and the interaction p ... [Phys. Rev. B 84, 224405 ] published .
Resonant generation of coherent phonons in a superconductor by ultrafast optical pump pulses: Andreas P. Schnyder, Dirk Manske, and Adolfo Avella
We study the generation of coherent phonons in a superconductor by ultrafast optical pump pulses. The nonequilibrium dynamics of the coupled Bogoliubov quasiparticle-phonon system after excitation with the pump pulse is analyzed by means of the density-matrix formalism with the phonons treated at a ... [Phys. Rev. B 84, 214513 ] published .
Theory of magnetization precession induced by a picosecond strain pulse in ferromagnetic semiconductor (Ga,Mn)As: T. L. Linnik, A. V. Scherbakov, D. R. Yakovlev, X. Liu, J. K. Furdyna et al.
A theoretical model of the coherent precession of magnetization excited by a picosecond acoustic pulse in a ferromagnetic semiconductor layer of (Ga,Mn)As is developed. The short strain pulse injected into the ferromagnetic layer modifies the magnetocrystalline anisotropy resulting in a tilt of the ... [Phys. Rev. B 84, 214432 ] published .
Energy dissipation in dielectrics after swift heavy-ion impact: A hybrid model: O. Osmani, N. Medvedev, M. Schleberger, and B. Rethfeld
The energy dissipation after irradiation of dielectrics with swift heavy ions is studied applying a combination of the Monte Carlo (MC) method and the two-temperature model (TTM). Within the MC calculation the transient dynamics of the electrons in the excited dielectric is described: the primary ex ... [Phys. Rev. B 84, 214105 ] published .
Depth-profiling of elastic and optical inhomogeneities in transparent materials by picosecond ultrasonic interferometry: Theory: V. Gusev, A. M. Lomonosov, P. Ruello, A. Ayouch, and G. Vaudel
The theoretical backgrounds for the depth-profiling of the optically transparent materials by picosecond ultrasonic interferometry are developed. The mathematical description of the light reflection from inhomogeneous transparent films or coatings is proposed. The inhomogeneity can be caused both by ... [J. Appl. Phys. 110, 124908 (2011)] published Tue Dec 20, 2011.
Generation of inhomogeneous plane shear acoustic modes by laser-induced thermoelastic gratings at the interface of transparent and opaque solids: Mansour Kouyate, Thomas Pezeril, Denis Mounier, and Vitalyi Gusev
The detailed theoretical description of how picosecond plane shear acoustic fronts can be excited by ultrafast lasers at the interface of two isotropic media, a transparent medium and an opaque medium, is presented. The processes leading to the emission of inhomogeneous plane bulk shear acoustic mod ... [J. Appl. Phys. 110, 123526 (2011)] published Wed Dec 28, 2011.
Hot carriers relaxation in highly excited polar semiconductors: Hot phonons versus phononplasmon coupling: Eric Tea, Hani Hamzeh, and Frederic Aniel
We present a study of the photo-excited charge carriers relaxation dynamics in polar semiconductors comparing calculations to pump probe experiments. Hot carrier densities in the 10cm range can easily be photo-generated using moderately intense optical excitations. This can lead to known phenomena, ... [J. Appl. Phys. 110, 113108 (2011)] published Thu Dec 8, 2011.
Fast switching of magnetization in the ferromagnetic semiconductor (Ga,Mn)(As,P) using nonequilibrium phonon pulses: A. Casiraghi, P. Walker, A. V. Akimov, K. W. Edmonds, A. W. Rushforth et al.
We use short acoustic pulses to induce a fast irreversible switching of the magnetization orientation in a layer of (Ga,Mn)(As,P). The pulses are generated by femtosecond optical excitation of a metal transducer film and travel ballistically through the sample. We show that the switching is triggere ... [Appl. Phys. Lett. 99, 262503 (2011)] published Wed Dec 28, 2011.
Observations of laser induced magnetization dynamics in Co/Pd multilayers with coherent x-ray scattering: B. Wu, D. Zhu, Y. Acremann, T. A. Miller, A. M. Lindenberg et al.
We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 5 ... [Appl. Phys. Lett. 99, 252505 (2011)] published Thu Dec 22, 2011.
Temperature and size dependence of time-resolved exciton recombination in ZnO quantum dots: I. Musa, F. Massuyeau, L. Cario, J. L. Duvail, S. Jobic et al.
ZnO nanocrystals with various sizes were prepared and characterized. Their photoluminescence dynamics has been investigated at low temperatures. For the smallest particles (3 nm), a defect-induced long-lived photoluminescence occurs around 2.5 eV which is slowed down at decay times longer than 3 ns ... [Appl. Phys. Lett. 99, 243107 (2011)] published Wed Dec 14, 2011.
Incoherence induced by phonon excitations in domain-growth dynamics: Role of the domain center-of-gravity motion: K. Iwano
An ultrafast growth dynamics of a quantum domain after visible or near-infrared photoexcitation is discussed in a one-dimensional system that resides on the first-order phase boundary. Special emphasis is placed on the effects of phonon excitations that are expected to occur in the course of the dyn ... [Phys. Rev. B 84, 235139 ] published .
Saturation effects in femtosecond laser ablation of silicon-on-insulator: Hao Zhang, D. van Oosten, D. M. Krol, and J. I. Dijkhuis
We report a surface morphology study on single-shot submicron features fabricated on silicon on insulator by tightly focused femtosecond laser pulses. In the regime just below single-shot ablation threshold nano-tips are formed, whereas in the regime just above single-shot ablation threshold, a satu ... [Appl. Phys. Lett. 99, 231108 (2011)] published Thu Dec 8, 2011.
The influence of charged InAs quantum dots on the conductance of a two-dimensional electron gas: Mobility vs. carrier concentration: B. Marquardt, A. Beckel, A. Lorke, A. D. Wieck, D. Reuter et al.
Using time-resolved transport spectroscopy, we investigate the influence of charge-tunable InAs quantum dots (QDs) on the conductance of a nearby two-dimensional electron gas (2DEG). Loading successively electrons into the self-assembled QDs decreases the carrier concentration and mobility in the 2D ... [Appl. Phys. Lett. 99, 223510 (2011)] published Wed Nov 30, 2011.
Ultrafast decay of high frequency optical phonon mode in KTiOPO: Shan Yang (杨山), Sanjay Adhikari, Manoj Dobbala, and Feruz Ganikhanov
Decay of the strongest optical phonon mode in KTiOPO was directly traced using femtosecond coherent anti-Stokes Raman scattering spectroscopy. Dephasing of the Raman active mode at ~700 cm proceeds with the nonlinear polarization dephasing time of 495 10 fs. The dephasing is solely due to the phono ... [Appl. Phys. Lett. 99, 221903 (2011)] published Mon Nov 28, 2011.
Carrier Relaxation in Epitaxial Graphene Photoexcited Near the Dirac Point: S. Winnerl, M. Orlita, P. Plochocka, P. Kossacki, M. Potemski et al.
We study the carrier dynamics in epitaxially grown graphene in the range of photon energies from 10 to 250 meV. The experiments complemented by microscopic modeling reveal that the carrier relaxation is significantly slowed down as the photon energy is tuned to values below the optical-phonon freque ... [Phys. Rev. Lett. 107, 237401 ] published .
Dependence of Resonance Energy Transfer on Exciton Dimensionality: Jan Junis Rindermann, Galia Pozina, Bo Monemar, Lars Hultman, Hiroshi Amano et al.
We investigate the dependence of resonance energy transfer from Wannier-Mott excitons to an organic overlayer on exciton dimensionality. We exploit the excitonic potential disorder in a single quantum well to tune the balance between localized and free excitons by scaling the Boltzmann distribution ... [Phys. Rev. Lett. 107, 236805 ] published .
Micromagnetic study of current-pulse-induced magnetization switching in magnetic tunnel junctions with antiferromagnetically and ferromagnetically coupled synthetic free layers: Chikako Yoshida, Young Min Lee, Takao Ochiai, Yuji Uehara, and Toshihiro Sugii
We investigated the dynamics of current-pulse-induced magnetization switching in magnetic tunnel junctions (MTJs) with antiferromagnetically and ferromagnetically coupled synthetic free layers through micromagnetic simulations. We found that a magnetic vortex is formed in thick upper ferromagnetic l ... [Appl. Phys. Lett. 99, 222505 (2011)] published Mon Nov 28, 2011.
Quantum Dynamics of a Driven Correlated System Coupled to Phonons: L. Vidmar, J. BonCa, T. Tohyama, and S. Maekawa
Nonequilibrium interplay between charge, spin, and lattice degrees of freedom on a square lattice is studied for a single charge carrier doped in the t-J-Holstein model. In the presence of a static electric field we calculate the quasistationary state. With increasing electron-phonon (e-ph) coupling ... [Phys. Rev. Lett. 107, 246404 ] published .
Time-resolved plasma measurements in Ge-doped silica exposed to infrared femtosecond laser: M. Lancry, N. Groothoff, B. Poumellec, S. Guizard, N. Fedorov et al.
Using a time-resolved interferometric technique, we study the laser-induced carrier-trapping dynamics in SiO and Ge-doped SiO. The fast trapping of electrons in the band gap is associated with the formation of self-trapped excitons (STE). The STE trapping is doping dependent in SiO. The mean trappin ... [Phys. Rev. B 84, 245103 ] published .
State-resolved observation in real time of the structural dynamics of multiexcitons in semiconductor nanocrystals: Samuel L. Sewall, Ryan R. Cooney, Eva A. Dias, Pooja Tyagi, and Patanjali Kambhampati
Biexciton processes in semiconductor nanocrystals, e.g. optical gain, are widely treated as arising from structureless biexcitons. We challenge this view by observing the binding energies of hot biexcitons in CdSe nanocrystals. These experiments reveal a previously unobserved spectrum in the biexcit ... [Phys. Rev. B 84, 235304 ] published .
Redshift in the Optical Absorption of ZnO Single Crystals in the Presence of an Intense Midinfrared Laser Field: Shambhu Ghimire, Anthony D. DiChiara, Emily Sistrunk, Urszula B. Szafruga, Pierre Agostini et al.
We report time-resolved electroabsorption of a weak probe in a 500 [mu]m thick zinc-oxide crystal in the presence of a strong midinfrared pump in the tunneling limit. We observe a substantial redshift in the absorption edge that scales with the cube root of intensity up to 1 TW/cm (0.38 eV cm TW) ... [Phys. Rev. Lett. 107, 167407 ] published .
Detailed calculation of hydroxyl (OH) radical two-photon absorption via broadband ultrafast excitation: Hans U. Stauffer, Sukesh Roy, Waruna D. Kulatilaka, and James R. Gord
The theoretical framework for calculation of two-photon absorption cross sections for intermediate Hund's cases (a) and (b) diatomic species is described in detail and applied toward the hydroxyl (OH) radical. Analytical expressions are derived for the 20 rotational branches that are present in the ... [J. Opt. Soc. Am. B 29, 40 (2011)] published Tue Dec 27, 2011.
Tailoring terahertz radiation by controlling tunnel photoionization events in gases: I Babushkin, S Skupin, A Husakou, C Khler, E Cabrera-Granado et al.
Various applications ranging from nonlinear terahertz (THz) spectroscopy to remote sensing require broadband and intense THz radiation, which can be generated by focusing two-color laser pulses into a gas. In this setup, THz radiation originates from the buildup of electron density in sharp steps of ... [New J. Phys. 13, 123029 (2011)] published Thu Dec 29, 2011.
Exploring Interatomic Coulombic Decay by Free Electron Lasers: Philipp V. Demekhin, Spas D. Stoychev, Alexander I. Kuleff, and Lorenz S. Cederbaum
To exploit the high intensity of laser radiation, we propose to select frequencies at which single-photon absorption is of too low energy and two or more photons are needed to produce states of an atom that can undergo interatomic Coulombic decay (ICD) with its neighbors. For Ne it is explicitly dem ... [Phys. Rev. Lett. 107, 273002 ] published .
Evolution of superpositions of quantum states through a level crossing: B. T. Torosov and N. V. Vitanov
The Landau-Zener-Stuckelberg-Majorana (LZSM) model is widely used for estimating transition probabilities in the presence of crossing energy levels in quantum physics. This model, however, makes the unphysical assumption of an infinitely long constant interaction, which introduces a divergent phase ... [Phys. Rev. A 84, 063411 ] published .
Generating Molecular Rovibrational Coherence by Two-Photon Femtosecond Photoassociation of Thermally Hot Atoms: Leonid Rybak, Saieswari Amaran, Liat Levin, Michal Tomza, Robert Moszynski et al.
The formation of diatomic molecules with rotational and vibrational coherence is demonstrated experimentally in free-to-bound two-photon femtosecond photoassociation of hot atoms. In a thermal gas at a temperature of 1000 K, pairs of magnesium atoms, colliding in their electronic ground state, are e ... [Phys. Rev. Lett. 107, 273001 ] published .
Control of Molecular Rotation with a Chiral Train of Ultrashort Pulses: S. Zhdanovich, A. A. Milner, C. Bloomquist, J. Floss, I. Sh. Averbukh et al.
Trains of ultrashort laser pulses separated by the time of rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a chiral pulse traina sequence of linearly polarized pulses with the polarization direction rotati ... [Phys. Rev. Lett. 107, 243004 ] published .
Differential study on molecular suppressed ionization in intense linearly and circularly polarized laser fields: Yongkai Deng, Yunquan Liu, Xianrong Liu, Hong Liu, Yudong Yang et al.
We present a differential study on above-threshold ionization of the O (N) molecule as well as the companion atom Xe (Ar) (with close ionization potential) produced by linearly and circularly polarized laser fields (25 fs, 795 nm). The photoelectron angular distributions of the companion target are ... [Phys. Rev. A 84, 065405 ] published .
Comparative investigation of third- and fifth-harmonic generation in atomic and molecular gases driven by midinfrared ultrafast laser pulses: Jielei Ni, Jinping Yao, Bin Zeng, Wei Chu, Guihua Li et al.
We report on the comparative experimental investigation on third- and fifth-harmonic generation (THG and FHG) in atomic and molecular gases driven by midinfrared ultrafast laser pulses at a wavelength of ~1500 nm. We observe that the conversion efficiencies of both the THG and FHG processes saturate ... [Phys. Rev. A 84, 063846 ] published .
Phase-dependent coherent population trapping and optical switching: J. Kou, R. G. Wan, Z. H. Kang, L. Jiang, L. Wang et al.
We propose a scheme for achieving phase-dependent coherent population trapping, showing that both the dark state of the atoms and light propagation dynamics depend on the relative phase of the fields. The atomic coherence prepared via adiabatic process plays a key role in the interaction of light wi ... [Phys. Rev. A 84, 063807 ] published .
Optimized control of multistate quantum systems by composite pulse sequences: G. T. Genov, B. T. Torosov, and N. V. Vitanov
We introduce a technique for derivation of high-fidelity composite pulse sequences for two types of multistate quantum systems: systems with the SU(2) and Morris-Shore dynamic symmetries. For the former type, we use the Majorana decomposition to reduce the dynamics to an effective two-state system, ... [Phys. Rev. A 84, 063413 ] published .
Competition between two-photon-resonant three-photon ionization and four-wave mixing in Xe: Hidekazu Nagai and Taisuke Nakanaga
Competitive inhibition of a resonance enhanced multiphoton ionization process by a resonant four-wave mixing has been observed in Xe atoms. When an intense IR (1064 nm) laser was applied to a sample of Xe which was also being irradiated by a UV laser tuned to the two-photon absorption line of Xe, th ... [Phys. Rev. A 84, 063408 ] published .
Field-free molecular alignment control by phase-shaped femtosecond laser pulse: Shian Zhang, Chenhui Lu, Tianqing Jia, Zhenrong Sun, and Jianrong Qiu
In this paper, we theoretically show that the field-free molecular alignment can be controlled by shaping the femtosecond laser pulse with a periodic phase step modulation, involving the maximum degree and temporal structure of the molecular alignment. We show that the molecular alignment can be com ... [J. Chem. Phys. 135, 224308 (2011)] published Wed Dec 14, 2011.
Circular Dichroism in Laser-Assisted Short-Pulse Photoionization: A. K. Kazansky, A. V. Grigorieva, and N. M. Kabachnik
A remarkable effect of circular dichroism, i.e., a difference in photoelectron spectra produced by right and left circularly polarized light in two-color multiphoton ionization of atoms, is predicted for the case when the atom is ionized by an extreme ultraviolet or x-ray femtosecond pulse in the fi ... [Phys. Rev. Lett. 107, 253002 ] published .
Enhanced Nonlinear Double Excitation of He in Intense Extreme Ultraviolet Laser Fields: A. Hishikawa, M. Fushitani, Y. Hikosaka, A. Matsuda, C.-N. Liu et al.
Nonlinear, three-photon double excitation of He in intense extreme ultraviolet free-electron laser fields (~24.1 eV, ~5 TW/cm) is presented. Resonances to the doubly excited states converging to the He N=3 level are revealed by the shot-by-shot photoelectron spectroscopy and identified by theoreti ... [Phys. Rev. Lett. 107, 243003 ] published .
Effects of pulse shape on strongly driven two-level systems: C. W. S. Conover
We present an experimental study of the dynamics of a two-level system driven by strong nonresonant electromagnetic pulses as a function of pulse intensity and detuning. We have explored the qualitative and quantitative behavior of the transition probability as a function of pulse area for five diff ... [Phys. Rev. A 84, 063416 ] published .
Rotational coherence imaging and control for CN molecules through time-frequency resolved coherent anti-Stokes Raman scattering: Johan Lindgren, Eero Hulkko, Mika Pettersson, and Toni Kiljunen
Numerical wave packet simulations are performed for studying coherent anti-Stokes Raman scattering (CARS) for CN radicals. Electronic coherence is created by femtosecond laser pulses between the X Sigma and B Sigma states. Due to the large energy separation of vibrational states, the wave packets ar ... [J. Chem. Phys. 135, 224514 (2011)] published Tue Dec 13, 2011.
Selective nonlinear response preparation using femtosecond spectrally resolved four-wave-mixing: Jan Philip Kraack, Marcus Motzkus, and Tiago Buckup
A novel method is presented to assist the assignment of vibrational coherence in the homodyne degenerate four-wave-mixing technique. The dependence of vibrational coherence dynamics on the interaction sequence of chirped pump and Stokes excitation pulses is exploited to distinguish quantum beating f ... [J. Chem. Phys. 135, 224505 (2011)] published Fri Dec 9, 2011.
Coherent control of molecular torsion: Shane M. Parker, Mark A. Ratner, and Tamar Seideman
We propose a coherent, strong-field approach to control the torsional modes of biphenyl derivatives, and develop a numerical scheme to simulate the torsional dynamics. By choice of the field parameters, the method can be applied either to drive the torsion angle to an arbitrary configuration or to i ... [J. Chem. Phys. 135, 224301 (2011)] published Thu Dec 8, 2011.
The electronic spectrum of SiH: Jahn-Teller Rydberg series: A. M. Velasco, C. Lavin, A. M. J. Sanchez de Meras, and J. Sanchez Marin
The aim of the present theoretical work is to provide data necessary for a better understanding of the electronic spectrum of the silane molecule, which is affected by the Jahn-Teller effect. By selecting an adequate distorted C geometry of SiH, the three lower Koopmans ionization potentials are eva ... [J. Chem. Phys. 135, 214304 (2011)] published Fri Dec 2, 2011.
Apparatus for laser-assisted electron scattering in femtosecond intense laser fields: Reika Kanya, Yuya Morimoto, and Kaoru Yamanouchi
An apparatus for observation of laser-assisted electron scattering (LAES) in femtosecond intense laser fields was developed. The unique apparatus has three essential components, i.e., a photocathode-type ultrashort pulsed-electron gun, a toroidal-type electron energy analyzer enabling simultaneous d ... [Rev. Sci. Instrum. 82, 123105 (2011)] published Tue Dec 13, 2011.
GHz Rabi Flopping to Rydberg States in Hot Atomic Vapor Cells: B. Huber, T. Baluktsian, M. Schlagmuller, A. Kolle, H. Kubler et al.
We report on the observation of Rabi oscillations to a Rydberg state on a time scale below 1 ns in thermal rubidium vapor. We use a bandwidth-limited pulsed excitation and observe up to 6 full Rabi cycles within a pulse duration of ~4 ns. We find good agreement between the experiment and numerical ... [Phys. Rev. Lett. 107, 243001 ] published .
Temporal analysis of nonresonant two-photon coherent control involving bound and dissociative molecular states: Jing Su, Shaohao Chen, Agnieszka Jaron-Becker, and Andreas Becker
We theoretically study the control of two-photon excitation to bound and dissociative states in a molecule induced by trains of laser pulses, which are equivalent to certain sets of spectral phase modulated pulses. To this end, we solve the time-dependent Schrodinger equation for the interaction of ... [Phys. Rev. A 84, 065402 ] published .
Exactly solvable model for nonlinear light-matter interaction in an arbitrary time-dependent field: J. M. Brown, A. Lotti, A. Teleki, and M. Kolesik
Exact analytic expressions are derived for the dipole moment and nonlinear current of a one-dimensional quantum particle subject to a short-range attractive potential and an arbitrary time-dependent electric field. An efficient algorithm for the current evaluation is described and a robust implement ... [Phys. Rev. A 84, 063424 ] published .
Dressed-bound-state molecular strong-field approximation: Application to above-threshold ionization of heteronuclear diatomic molecules: E. Hasovic, M. Busuladzic, W. Becker, and D. B. Milosevic
The molecular strong-field approximation (MSFA), which includes dressing of the molecular bound state, is introduced and applied to above-threshold ionization of heteronuclear diatomic molecules. Expressions for the laser-induced molecular dipole and polarizability as functions of the laser paramete ... [Phys. Rev. A 84, 063418 ] published .
Nonadiabatic tunneling in circularly polarized laser fields: Physical picture and calculations: Ingo Barth and Olga Smirnova
We consider selectivity of strong-field ionization in circularly polarized laser fields to the sense of electron rotation in the laser polarization plane in the initial state. We show that, in contrast to the textbook examples of one-photon ionization and bound-state excitations with increase in the ... [Phys. Rev. A 84, 063415 ] published .
Intensity-resolved ionization yields of aniline with femtosecond laser pulses: J. Strohaber, T. Mohamed, N. Hart, F. Zhu, R. Nava et al.
We present experimental results for the ionization of aniline and benzene molecules subjected to intense ultrashort laser pulses. Measured parent molecular ions yields were obtained using a recently developed technique capable of three-dimensional imaging of ion distributions within the focus of a l ... [Phys. Rev. A 84, 063414 ] published .
Unveiling and Driving Hidden Resonances with High-Fluence, High-Intensity X-Ray Pulses: E. P. Kanter, B. Krassig, Y. Li, A. M. March, P. Ho et al.
We show that high fluence, high-intensity x-ray pulses from the world's first hard x-ray free-electron laser produce nonlinear phenomena that differ dramatically from the linear x-raymatter interaction processes that are encountered at synchrotron x-ray sources. We use intense x-ray pulses of sub-10 ... [Phys. Rev. Lett. 107, 233001 ] published .
Parity-selective enhancement of field-free molecular orientation in an intense two-color laser field: Hyeok Yun, Hyung Taek Kim, Chul Min Kim, Chang Hee Nam, and Jongmin Lee
We investigated the characteristics of molecular orientation induced by a nonresonant two-color femtosecond laser field. By analyzing the rotational dynamics of asymmetric linear molecules, we revealed that the critical parameter in characterizing the molecular orientation was the hyperpolarizabilit ... [Phys. Rev. A 84, 065401 ] published .
Enhancing photoassociation efficiency by using a picosecond laser pulse with cubic-phase modulation: Wei Zhang (张为), Ting Xie (谢廷), Yin Huang (黄寅), and Shu-Lin Cong (丛书林)
The photoassociation (PA) dynamics of ultracold cesium atoms steered by the picosecond laser pulse with cubic-phase modulation has been investigated theoretically by solving numerically the time-dependent Schrodinger equation using the mapped Fourier grid method. The temporal duration of the pulse i ... [Phys. Rev. A 84, 065406 ] published .
Vibrational dynamics of the bending mode of water interacting with ions: L. Piatkowski and H. J. Bakker
We studied the vibrational relaxation dynamics of the bending mode (nu) of the HO water molecules in the presence of different salts (LiCl, LiBr, LiI, NaI, CsI, NaClO, and NaBF). The linear and nonlinear spectra of the bending mode show distinct responses of water molecules hydrating the anions. We ... [J. Chem. Phys. 135, 214509 (2011)] published Wed Dec 7, 2011.
Spectroscopic characterization of the first ultrafast catalytic intermediate in protochlorophyllide oxidoreductase: Olga A. Sytina, Ivo H. M. van Stokkum, Derren J. Heyes, C. Neil Hunter, and Marie Louise Groot
The enzyme NADPH:protochlorophyllide oxidoreductase (POR) catalyses the reduction of protochlorophyllide into chlorophyllide, a precursor of chlorophyll a in photosynthetic organisms. The enzyme binds the substrate and the cofactor in the dark and catalysis is initiated by the absorption of light by ... [Phys. Chem. Chem. Phys. 14, 616 (2011)] published Fri Dec 9, 2011.
On the nature and signatures of the solvated electron in water: B. Abel, U. Buck, A. L. Sobolewski, and W. Domcke
The hydrated electron is one of the simplest chemical transients and has been the subject of intense investigation and speculation since its discovery in 1962 by Hart and Boag. Although extensive kinetic and spectroscopic research on this species has been reported for many decades, its structure, i. ... [Phys. Chem. Chem. Phys. 14, 22 (2011)] published Mon Dec 5, 2011.
Initiation and control of catalytic surface reactions with shaped femtosecond laser pulses: Patrick Nuernberger, Daniel Wolpert, Horst Weiss, and Gustav Gerber
We report on femtosecond laser-induced catalytic reactions of carbon monoxide and hydrogen on single crystal surfaces under high vacuum conditions. Several product molecules are synthesized, among them also species for whose formation at least three reactants are required. By applying closed-loop op ... [Phys. Chem. Chem. Phys. 14, 1185 (2011)] published Fri Dec 16, 2011.
Complexes of tetracyclines with divalent metal cations investigated by stationary and femtosecond-pulsed techniques: Benedetta Carlotti, Alessio Cesaretti, and Fausto Elisei
Spectroscopic techniques both in steady-state (in absorption and emission) and pulsed (absorption of excited states with femtosecond resolution) conditions were used to study the complexation process between six molecules belonging to the tetracycline family and Mg; in the case of TC the study was e ... [Phys. Chem. Chem. Phys. 14, 823 (2011)] published Fri Dec 9, 2011.
Excited-state dynamics of phenolpyridinium biaryl: Jean-Pierre Malval, Helene Chaumeil, Wolfgang Rettig, Vladimir Kharlanov, Vincent Diemer et al.
The excited-state dynamics of a donoracceptor phenolpyridinium biaryl cation was investigated in various solvents by femtosecond transient absorption spectroscopy and temperature dependent steady-state emission measurements. After excitation to a near-planar FranckCondon delocalized excited S(DE) st ... [Phys. Chem. Chem. Phys. 14, 562 (2011)] published Fri Dec 9, 2011.
Probing structural evolution along multidimensional reaction coordinates with femtosecond stimulated Raman spectroscopy: Renee R. Frontiera, Chong Fang, Jyotishman Dasgupta, and Richard A. Mathies
Mapping out multidimensional potential energy surfaces has been a goal of physical chemistry for decades in the quest to both predict and control chemical reactivity. Recently a new spectroscopic approach called Femtosecond Stimulated Raman Spectroscopy or FSRS was introduced that can structurally i ... [Phys. Chem. Chem. Phys. 14, 405 (2011)] published Fri Dec 9, 2011.
Transient infrared spectroscopy: a new approach to investigate valence tautomerism: Touron Touceda Patricia, Mosquera Vazquez Sandra, Lima Manuela, Lapini Andrea, Foggi Paolo et al.
In this work we present, to our knowledge for the first time, the results of a transient infrared spectroscopic study of the photoinduced valence tautomerism process in cobaltdioxolene complexes with sub-picosecond time resolution. The molecular systems investigated were [Co(tpa)(diox)]PF (1) and [C ... [Phys. Chem. Chem. Phys. 14, 1038 (2011)] published Fri Dec 9, 2011.
Using shaped ultrafast laser pulses to detect enzyme binding: Chien-hung Tseng, Thomas C. Weinacht, Anna E. Rhoades, Matthew Murray, and Brett J. Pearson
We use multiphoton quantum-control spectroscopy to discriminate between unbound and enzyme-bound NADH (reduced nicotinamide adenine dinucleotide) molecules in solution. Shaped ultrafast laser pulses are used to illuminate both forms of NADH, and the ratio of the fluorescence from the bound and unbou ... [Opt. Express 19, 24638 (2011)] published Thu Dec 1, 2011.
Spectral modulation observed in Chl-a by ultrafast laser spectroscopy: Juan Du, Kazuaki Nakata, Yongliang Jiang, Eiji Tokunaga, and Takayoshi Kobayashi
Broadband real-time dynamic vibronic coupling in Chl-a were experimentally studied using few cycle laser pulses of 6.8fs duration and a 128-channnel lock-in amplifier. Thanks to the extreme temporal resolution benefitting from the ultrashort laser pulse, the real-time modulation of the electronic tr ... [Opt. Express 19, 22480 (2011)] published Thu Dec 1, 2011.
Photoinduced Neutral-to-Ionic Phase Transition in Tetrathiafulvalene-p-chloranil Studied by Time-Resolved Vibrational Spectroscopy: Yoshitaka Matsubara, Yoichi Okimoto, Tatsushi Yoshida, Tadahiko Ishikawa, Shin-ya Koshihara et al.
We studied the photoinduced neutral-to-ionic phase transition in tetrathiafulvalene-p-chloranil (TTF-CA) using time-resolved infrared (IR) vibrational spectroscopy with a broadband femtosecond IR laser pulse and a linear IR detector array. After photoexcitation, the strength of the TTF a_{g}\nu_{3} ... [J. Phys. Soc. Jpn. 80, 124711 (2011)] published Tue Dec 13, 2011.
Charge-Transfer State and Charge Dynamics in Poly(9,9'-dioctylfluorene-co-bithiophene) and [6,6]-Phenyl C-butyric Acid Methyl Ester Blend Film: Kouhei Yonezawa, Minato Ito, Hayato Kamioka, Takeshi Yasuda, Liyuan Han et al.
Bulk heterojunction (BHJ) based on a donor (D) polymer and acceptor (A) fullerene derivative is a promising organic photovoltaics. Here, we performed femtosecond time-resolved spectroscopy of poly(9,9'-dioctylfluorene-co-bithiophene) (F8T2)/[6,6]-phenyl C-butyric acid methyl ester (PCBM) blend film ... [Appl. Phys. Express 4, 122601 (2011)] published Tue Dec 13, 2011.
Individual bioaerosol particle discrimination by multi-photon excited fluorescence: Denis Kiselev, Luigi Bonacina, and Jean-Pierre Wolf
Femtosecond laser induced multi-photon excited fluorescence (MPEF) from individual airborne particles is tested for the first time for discriminating bioaerosols. The fluorescence spectra, analysed in 32 channels, exhibit a composite character originating from simultaneous two-photon and three-photo ... [Opt. Express 19, 24516 (2011)] published Thu Dec 1, 2011.
Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements: Anton Barty, Carl Caleman, Andrew Aquila, Nicusor Timneanu, Lukas Lomb et al.
X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis. For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been pred ... [Nat. Photonics 6, 35 (2011)] published Thu Dec 22, 2011.
Multiple time scale molecular dynamics for fluids with orientational degrees of freedom. II. Canonical and isokinetic ensembles: Igor P. Omelyan and Andriy Kovalenko
We have developed several multiple time stepping techniques to overcome the limitations on efficiency of molecular dynamics simulations of complex fluids. They include the modified canonical and isokinetic schemes, as well as the extended isokinetic Nose-Hoover chain approach. The latter generalizes ... [J. Chem. Phys. 135, 234107 (2011)] published Mon Dec 19, 2011.
Structural dynamics of surfaces by ultrafast electron crystallography: Experimental and multiple scattering theory: Sascha Schafer, Wenxi Liang, and Ahmed H. Zewail
Recent studies in ultrafast electron crystallography (UEC) using a reflection diffraction geometry have enabled the investigation of a wide range of phenomena on the femtosecond and picosecond time scales. In all these studies, the analysis of the diffraction patterns and their temporal change after ... [J. Chem. Phys. 135, 214201 (2011)] published Fri Dec 2, 2011.
Theory of quantum energy transfer in spin chains: Superexchange and ballistic motion: Claire X. Yu, Lian-Ao Wu, and Dvira Segal
Quantum energy transfer in a chain of two-level (spin) units, connected at its ends to two thermal reservoirs, is analyzed in two limits: (i) in the off-resonance regime, when the characteristic subsystem excitation energy gaps are larger than the reservoirs frequencies, or the baths temperatures ar ... [J. Chem. Phys. 135, 234508 (2011)] published Mon Dec 19, 2011.
The dependence of singlet exciton relaxation on excitation density and temperature in polycrystalline tetracene thin films: Kinetic evidence for a dark intermediate state and implications for singlet fission: Jonathan J. Burdett, David Gosztola, and Christopher J. Bardeen
The excited state dynamics of polycrystalline tetracene films are studied using femtosecond transient absorption in combination with picosecond fluorescence, continuing work reported in an earlier paper [J. J. Burdett, A. M. Muller, D. Gosztola, and C. J. Bardeen, J. Chem. Phys. 133, 144506 (2010)]. ... [J. Chem. Phys. 135, 214508 (2011)] published Wed Dec 7, 2011.
Competitive ionization processes of anthracene excited with a femtosecond pulse in the multi-photon ionization regime: M. Goto and K. Hansen
To clarify the ionization mechanism of large molecules under multi-photon ionization conditions, photo-electron spectroscopic studies on anthracene have been performed with electron imaging technique. Electron kinetic energy distributions below a few eV reveal that three kinds of ionization channels ... [J. Chem. Phys. 135, 214310 (2011)] published Tue Dec 6, 2011.
Efficient electron dynamics with the planewave-based real-time time-dependent density functional theory: Absorption spectra, vibronic electronic spectra, and coupled electron-nucleus dynamics: Seung Kyu Min, Yeonchoo Cho, and Kwang S. Kim
The electron dynamics with complex third-order Suzuki-Trotter propagator (ST) has been implemented into a planewave (PW) based density functional theory program, and several applications including linear absorption spectra and coupled electron-nucleus dynamics have been calculated. Since the ST redu ... [J. Chem. Phys. 135, 244112 (2011)] published Fri Dec 30, 2011.
Ultrafast Dynamics of Photoionized Acetylene: Mohamed El-Amine Madjet, Oriol Vendrell, and Robin Santra
Acetylene cations [HCCH] produced in the ASigma state by extreme ultraviolet (XUV) photoionization are investigated theoretically, based on a mixed quantum-classical approach. We show that the decay of the ASigma state occurs via both ultrafast isomerization and nonradiative electronic relaxation. W ... [Phys. Rev. Lett. 107, 263002 ] published .
Chasing charge localization and chemical reactivity following photoionization in liquid water: Ondrej Marsalek, Christopher G. Elles, Piotr A. Pieniazek, Eva Pluharova, Joost VandeVondele et al.
The ultrafast dynamics of the cationic hole formed in bulk liquid water following ionization is investigated by ab initio molecular dynamics simulations and an experimentally accessible signature is suggested that might be tracked by femtosecond pump-probe spectroscopy. This is one of the fastest fu ... [J. Chem. Phys. 135, 224510 (2011)] published Mon Dec 12, 2011.
Radiation damage in protein serial femtosecond crystallography using an x-ray free-electron laser: Lukas Lomb, Thomas R. M. Barends, Stephan Kassemeyer, Andrew Aquila, Sascha W. Epp et al.
X-ray free-electron lasers deliver intense femtosecond pulses that promise to yield high resolution diffraction data of nanocrystals before the destruction of the sample by radiation damage. Diffraction intensities of lysozyme nanocrystals collected at the Linac Coherent Light Source using 2 keV pho ... [Phys. Rev. B 84, 214111 ] published .
Subharmonic excitation in amplitude modulation atomic force microscopy in the presence of adsorbed water layers: Sergio Santos, Victor Barcons, Albert Verdaguer, and Matteo Chiesa
In ambient conditions, nanometric water layers form on hydrophilic surfaces covering them and significantly changing their properties and characteristics. Here we report the excitation of subharmonics in amplitude modulation atomic force microscopy induced by intermittent water contacts. Our simulat ... [J. Appl. Phys. 110, 114902 (2011)] published Fri Dec 2, 2011.
Nonequilibrium Fermi golden rule for electronic transitions through conical intersections: Artur F. Izmaylov, David MendiveTapia, Michael J. Bearpark, Michael A. Robb, John C. Tully et al.
We consider photoinduced electronic transitions through conical intersections in large molecules. Starting from the linear vibronic model Hamiltonian and treating linear diabatic couplings within the second order cumulant expansion, we have developed a simple analytical expression for the time evolu ... [J. Chem. Phys. 135, 234106 (2011)] published Mon Dec 19, 2011.
High-power 200 fs Kerr-lens mode-locked Yb:YAG thin-disk oscillator: O. Pronin, J. Brons, C. Grasse, V. Pervak, G. Boehm et al.
We demonstrate a power-scalable Kerr-lens mode-locked Yb:YAG thin-disk oscillator. It delivers 200 fs pulses at an average power of 17 W and a repetition rate of 40 MHz. At an increased (180 W) pump power level, the laser produces 270 fs 1.1 [mu]J pulses at an average power of 45 W (optical-to-optic ... [Opt. Lett. 36, 4746 (2011)] published Tue Dec 20, 2011.
1 MHz repetition rate hollow fiber pulse compression to sub-100-fs duration at 100 W average power: Jan Rothhardt, Steffen Hadrich, Henning Carstens, Nicholas Herrick, Stefan Demmler et al.
We report on nonlinear pulse compression at very high average power. A high-power fiber chirped pulse amplification system based on a novel large pitch photonic crystal fiber delivers 700 fs pulses with 200 [mu]J pulse energy at a 1 MHz repetition rate, resulting in 200 W of average power. Subsequen ... [Opt. Lett. 36, 4605 (2011)] published Mon Dec 5, 2011.
Coherently-combined two channel femtosecond fiber CPA system producing 3 mJ pulse energy: Arno Klenke, Enrico Seise, Stefan Demmler, Jan Rothhardt, Sven Breitkopf et al.
We present a fiber CPA system consisting of two coherently combined fiber amplifiers, which have been arranged in an actively stabilized Mach-Zehnder interferometer. Pulse durations as short as 470 fs and pulse energies of 3 mJ, corresponding to 5.4 GW of peak power, have been achieved at an average ... [Opt. Express 19, 24280 (2011)] published Thu Dec 1, 2011.
Femtosecond VECSEL with tunable multi-gigahertz repetition rate: Oliver D. Sieber, Valentin J. Wittwer, Mario Mangold, Martin Hoffmann, Matthias Golling et al.
We present a femtosecond vertical external cavity surface emitting laser (VECSEL) that is continuously tunable in repetition rate from 6.5 GHz up to 11.3 GHz. The use of a low-saturation fluence semiconductor saturable absorber mirror (SESAM) enables stable cw modelocking with a simple cavity design ... [Opt. Express 19, 23538 (2011)] published Thu Dec 1, 2011.
Modelocked semiconductor laser system with pulse picking for variable repetition rate: J.C. Balzer, T. Schlauch, Th. Hoffmann, A. Klehr, G. Erbert et al.
The generation of picosecond pulses from a hybrid modelocked semiconductor master oscillator power amplifier system with a repetition rate as low as 340 kHz is presented. The fundamental repetition rate of the external cavity laser was 348 MHz and is reduced by an integrated ultrafast semiconductor ... [Electron. Lett. 47, 1387 ] published .
Femtosecond high-power spontaneous mode-locked operation in vertical-external cavity surface-emitting laser with gigahertz oscillation: Y. F. Chen, Y. C. Lee, H. C. Liang, K. Y. Lin, K. W. Su et al.
We realize a femtosecond high-power spontaneous mode-locked operation with gigahertz oscillation in a vertical-external cavity surface-emitting laser under the condition of eliminating the internal and external unwanted reflection. We find that the reflectivity of the output coupler has a significan ... [Opt. Lett. 36, 4581 (2011)] published Mon Dec 5, 2011.
High-power widely tunable sub-20fs Gaussian laser pulses for ultrafast nonlinear spectroscopy: Bernd Metzger, Andy Steinmann, and Harald Giessen
We demonstrate the generation of widely tunable sub-20fs Gaussian-shaped laser pulses using a grating-based 4-f pulse shaper and a liquid crystal spatial light modulator. Our pump source is an Yb:KGW solitary mode-locked oscillator at 44MHz repetition rate which is coupled into a large mode area mic ... [Opt. Express 19, 24354 (2011)] published Thu Dec 1, 2011.
Two-color deep-ultraviolet 40-fs pulses based on parametric amplification at 100 kHz: Huan Shen, Shunsuke Adachi, Takuya Horio, and Toshinori Suzuki
We present a 100-kHz deep-ultraviolet (DUV) laser system that generates 40-fs pulses. A 520-nm pulse generated by a noncollinear optical parametric amplifier pumped by the second harmonic of a Ti:sapphire laser is converted into 226- and 260-nm DUV pulses simultaneously with pulse energies of 250 an ... [Opt. Express 19, 22637 (2011)] published Thu Dec 1, 2011.
Mid-infrared laser-driven broadband water-window supercontinuum generation from pre-excited medium: Yang Li, Weiyi Hong, Qingbin Zhang, Shaoyi Wang, and Peixiang Lu
We theoretically investigate the broadband water-window supercontinuum generation from pre-excited medium with a mid-infrared pulse. We find that the wavelength scaling of the harmonic yield from near-visible (0.8 [mu]m) to mid-infrared (1.8 [mu]m) in single-atom level is lambda. Using an intense ph ... [Opt. Express 19, 24376 (2011)] published Thu Dec 1, 2011.
Coherent single-cycle pulses with MV/cm field strengths from a relativistic transition radiation light source: Matthias C. Hoffmann, Sebastian Schulz, Stephan Wesch, Steffen Wunderlich, Andrea Cavalleri et al.
Terahertz (THz) pulses with energies up to 100 [mu]J and corresponding electric fields up to 1 MV/cm were generated by coherent transition radiation from 500 MeV electron bunches at the free-electron laser Freie-Elektronen-Laser in Hamburg (FLASH). The pulses were characterized in the time domain by ... [Opt. Lett. 36, 4473 (2011)] published Mon Dec 5, 2011.
Coherent x-ray generation from below-threshold harmonics: Ji-Cai Liu, Markus C. Kohler, Christoph H. Keitel, and Karen Z. Hatsagortsyan
The possibility of x-ray emission employing below-threshold-harmonic generation in the nontunneling regime is considered. The interaction of a tightly bound valence electron in a highly charged ion with intense extreme-ultraviolet laser radiation is investigated in the weakly relativistic regime by ... [Phys. Rev. A 84, 063817 ] published .
Tunable and collimated terahertz radiation generation by femtosecond laser pulses: Hitendra K. Malik and Anil K. Malik
A mechanism is proposed for the generation of tunable terahertz (THz) radiation under the application of two femtosecond laser pulses and an external magnetic field, where quick tunnel ionization is achieved that leads to higher plasma density evolution and large residual current for the efficient T ... [Appl. Phys. Lett. 99, 251101 (2011)] published Mon Dec 19, 2011.
Vertical cavity surface emitting lasers with the active layer position detuned from standing wave antinode for picosecond pulse generation by gain switching: Boris S. Ryvkin, Eugene A. Avrutin, and Juha T. Kostamovaara
A vertical cavity surface emitting laser with the active layer position detuned from the standing wave antinode is proposed for the purpose of high energy picosecond pulse generation by gain switching and analysed using numerical simulations and a fully analytical model. An optimum value of the conf ... [J. Appl. Phys. 110, 123101 (2011)] published Mon Dec 19, 2011.
Multiscale multimodal imaging with multiphoton microscopy and optical coherence tomography: Shuo Tang, Yifeng Zhou, Kenny K. H. Chan, and Tom Lai
A multiscale multiphoton microscopy (MPM) and optical coherence tomography (OCT) system has been developed using a sub-10 fs Ti:sapphire laser. The system performs cross-sectional OCT imaging over millimeter field-of-view and en-face high-resolution MPM imaging with submicrometer resolution from the ... [Opt. Lett. 36, 4800 (2011)] published Tue Dec 20, 2011.
Test of the all-optical control of waveparticle duality of cavity photons by ordinary photodetection: O. Di Stefano, A. Ridolfo, S. Portolan, and S. Savasta
The principle of complementarity refers to the ability of quantum entities to behave as particles or waves under different experimental conditions. We present a proposal for the experimental observation of the ultrafast all-optical control of the waveparticle duality of light. The device is constitu ... [Opt. Lett. 36, 4509 (2011)] published Mon Dec 5, 2011.
Terahertz pinch harmonics enabled by single nano rods: Hyeong-Ryeol Park, Young-Mi Bahk, Jong Ho Choe, Sanghoon Han, Seong Soo Choi et al.
A pinch harmonic (or guitar harmonic) is a musical note produced by lightly pressing the thumb of the picking hand upon the string immediately after it is picked [J. Chem. Educ. 84, 1287 (2007)]. This technique turns off the fundamental and all overtones except those with a node at that location. He ... [Opt. Express 19, 24775 (2011)] published Thu Dec 1, 2011.

Latest News in Science (Australian Broadcasting Corporation)

Latest news in science as it happens from around Australia and the world.

Green tea drinkers more agile: Mon, 06 Feb 2012 14:07:00 +1100 - STAYING ABLE: Elderly adults who regularly drink green tea may stay more agile and independent than their peers over time.
Tree rings show extreme weather on the rise: Mon, 06 Feb 2012 11:18:00 +1100 - SILENT SENTINELS: Periods of droughts and flooding rains could become more common in south-eastern Australia and New Zealand.
Malaria toll far higher than thought: Mon, 06 Feb 2012 10:00:00 +1100 - BATTLE CONTINUES: Malaria kills nearly 50 per cent more than previously thought, claims a new investigation.
Fourth 'habitable' planet close to home: Fri, 03 Feb 2012 11:38:00 +1100 - EARTHLY NEIGHBOUR: Astronomers have found the fourth potentially habitable planet outside our solar system, only 22 light-years from Earth.
Survey finds jellyfish takeover exaggerated: Fri, 03 Feb 2012 10:20:00 +1100 - WOBBLY NUMBERS: Jellyfish might be able to shut down a nuclear-powered aircraft carrier, but they are not taking over the world's oceans and turning them into slime, say scientists.
Warming boosts some coral growth: Fri, 03 Feb 2012 06:00:00 +1100 - REVERSE TREND: Coral growth rates are increasing on some reefs off the coast of Western Australia, a new study has found.
Wet summer to continue for Eastern Australia: Thu, 02 Feb 2012 16:00:00 +1100 - RAINY DAYS: The current La Nina weather pattern is likely to continue for at least another month .
Design, not just threads, toughens web: Thu, 02 Feb 2012 11:56:00 +1100 - Scientists say they had unravelled the mystery of how spider webs can withstand multiple tears without collapsing.
Bring elephants to Australia?: Thu, 02 Feb 2012 06:00:00 +1100 - ECOLOGICAL RETHINK: Australia could introduce large herbivores such as elephants as part of a radical biological solution, says one expert.
Testosterone puts ego in driver's seat: Wed, 01 Feb 2012 15:28:00 +1100 - GOING SOLO: Testosterone can skew one's judgement, creating the impression that decisions are best taken alone .
Oldest known croc had shield-like head: Wed, 01 Feb 2012 10:30:00 +1100 - ANCIENT FLATHEAD: The oldest known species of crocodile had an armour-plated head and a body half the length of a train carriage.
Researchers tune into what brain hears: Wed, 01 Feb 2012 09:00:00 +1100 - BRAIN WAVES: US researchers have been able to reconstruct words by analysing brain activity.
What's taking ET so long to find us?: Tue, 31 Jan 2012 14:12:00 +1100 - HOME ALONE?: Mathematically speaking, ET should have found us by now.
Scientists shift on brain speech centre: Tue, 31 Jan 2012 11:22:00 +1100 - NEW INSIGHTS: The part of the brain used for speech processing is in a different location than originally believed, according to a US study.
Blue whales keep getting bigger: Tue, 31 Jan 2012 07:00:00 +1100 - SUPER-SIZING: Blue whales are the largest animal to have ever lived on Earth and - for now - are continuing to get bigger, say researchers.
No link between caesareans, weight: study: Mon, 30 Jan 2012 14:26:00 +1100 - Children born by Caesarean section are no more likely to become obese than if they are born vaginally, according to a Brazilian study.
Study puts the squeeze on vascular disease: Mon, 30 Jan 2012 11:00:00 +1100 - PRESSURE CHECK: Differences in systolic blood pressure between your left and right arm could be an early sign of increased risk of vascular disease, say UK researchers.
Extreme heat hurts wheat yields: Mon, 30 Jan 2012 09:40:00 +1100 - STRESSED GROWTH: Extreme heat can cause wheat crops to age faster and reduce yields, a US-led study shows.

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PHYSorg.com: Technology News

PhysOrg.com provides the latest news on technology, software, computer science, internet, semiconductor, telecom and science technology.

Bogus training offer opens hacker doors to bank accounts: Sun, 05 Feb 2012 06:40:01 EST - (PhysOrg.com) -- Mischief-making hackers, always willing to try clever ways to bypass advanced security safeguards, have figured out a way to make off like bandits, literally. According to a BBC report, the exploit first tricks account-owning victims by presenting offers of training for an upgraded security system. The hacker criminals, with their victims unaware, proceed to move money out of these users’ accounts.
Hackers block Slovenian largest bank NLB's website: Sun, 05 Feb 2012 06:10:02 EST - Online hackers' group Anonymous blocked temporarily on Saturday the website of Slovenia's largest bank NLB, while thousands protested in Ljubljana against an anti-piracy pact.
Mexico billionaires battle over telecoms sector: Sun, 05 Feb 2012 06:00:02 EST - Battles between three Mexican billionaires over control of the lucrative telecoms sector heated up again this week, intensified by international criticism of monopolistic practices.
Hackers apparently hit Swedish government site: Sun, 05 Feb 2012 05:50:01 EST - (AP) -- A group linked to the hacker network Anonymous says it has attacked the Swedish government's website and shut it down by overloading it.
British firms warned of Olympics Internet gaps: Sun, 05 Feb 2012 05:39:49 EST - British businesses are being warned of possible Internet breakdowns, data caps and "unavoidable" mobile phone problems during the London 2012 Olympics, in official advice from the Games organisers.
For Facebook 'Hacker Way' is way of life: Sun, 05 Feb 2012 05:37:53 EST - (AP) -- Facebook's billionaire CEO Mark Zuckerberg calls himself a hacker. For most people, that word means something malicious - shady criminals who listen in on private voicemails, or anonymous villains who cripple websites and break into email accounts.
Fold-it computer action set for Canada conference (w/ video): Sat, 04 Feb 2012 06:00:01 EST - (PhysOrg.com) -- What nonsense, sitting in front of one, single display screen and struggling with a split-screen view of multiple-sites plus data entry or word processing. Is this the way it has to be for doing papers, writing reports, presenting detailed stats, and collaborating with others? In 2012, the single-screen sit-down is the common user experience, not nonsense, but a concept presentation at an upcoming conference in Canada could change expectations for good.
Chips and apps on tap for Super Bowl: Sat, 04 Feb 2012 05:12:40 EST - Millions of American football fans will be watching the Super Bowl on television Sunday with one hand in the potato chips and the other holding a smartphone.
HP awards new CEO Whitman with $16.5M pay package: Sat, 04 Feb 2012 05:11:53 EST - Hewlett-Packard Co. ushered in Meg Whitman as its CEO with a $16.5 million compensation package that hinges on the one-time politician's ability to lift the stumbling technology company's stock price during the next two years.
Apple, Motorola in patent struggle in Germany: Sat, 04 Feb 2012 05:08:45 EST - Apple Inc. has temporarily blocked Motorola Mobility's attempt to have it withdraw several iPhone and iPad models from its Internet store in Germany, the latest twist in an extended legal duel over patents between the companies.
TV executives crave viewers who watch 2 screens: Fri, 03 Feb 2012 15:20:01 EST - Forget the small screen and the big screen. The hottest new thing in television is the "second screen" - the one on the tablet computer or cell phone that an increasing number of viewers keep an eye on while they're watching TV. And figuring out how to corral all those second-screeners and make money off them was the hottest topic at a recent convention of 5,000 television executives in Miami Beach.
Hackers hit Greek ministry over austerity, anti-piracy deal: Fri, 03 Feb 2012 15:10:01 EST - Online hackers group Anonymous on Friday attacked the Greek justice ministry website in criticism of the country's tough fiscal reforms and its decision to join a controversial anti-piracy deal.
Hackers deface website of lawyers for US Marine: Fri, 03 Feb 2012 14:40:35 EST - Members of the hacker group Anonymous defaced the website on Friday of the law firm that defended a US Marine who faced charges in connection with the 2005 killing of 24 Iraqi civilians.
Japanese entrepreneurs aim for Silicon Valley: Fri, 03 Feb 2012 12:00:01 EST - For an emerging generation of Japanese innovators, the dream isn't a job for life at a big company. They have new ambitions, and they're determined to go places. Especially Silicon Valley.
Poland freezes anti-piracy pact ratification: Fri, 03 Feb 2012 11:50:02 EST - Poland's prime minister said Friday that Warsaw would put on ice plans to ratify a controversial international online anti-piracy accord after massive off-and-online protests in his country.
Jointly utilizing LTE networks: Fri, 03 Feb 2012 11:20:49 EST - Data-intensive Internet applications on smartphones, tablets and laptops are more popular than ever before. The result: Traffic on the mobile network is increasing at a blinding speed. Intelligent technologies are intended to increase the data rates on the new LTE network. The solution is to use the mobile networks jointly.
EU probes new Google privacy policy: Fri, 03 Feb 2012 09:33:17 EST - The European Union's data protection authorities have asked Google to delay the rollout of its new privacy policy until they have verified that it doesn't break the bloc's data protection laws.
Hackers intercept FBI, Scotland Yard call (Update): Fri, 03 Feb 2012 09:31:43 EST - (AP) -- Trading jokes and swapping leads, investigators from the FBI and Scotland Yard spent the conference call strategizing about how to bring down the hacking collective known as Anonymous, responsible for a string of embarrassing attacks across the Internet.
A 'natural' solution for transportation: Fri, 03 Feb 2012 08:30:01 EST - As the United States transitions away from a primarily petroleum-based transportation industry, a number of different alternative fuel sources—ethanol, biodiesel, electricity and hydrogen—have each shown their own promise. Hoping to expand the pool even further, researchers at the U.S. Department of Energy's Argonne National Laboratory have begun to investigate adding one more contender to the list of possible energy sources for light-duty cars and trucks: compressed natural gas (CNG).
Judder-free videos on the smartphone: Fri, 03 Feb 2012 08:20:01 EST - Overloaded cellular networks can get annoying – especially when you want to watch a video on your smartphone. An optimised Radio Resource Manager will soon be able to help network operators accommodate heavy network traffic. Researchers will present their solution at the GSMA Mobile World Congress from 27 February to 1 March, 2012 in Barcelona.
Gamers on 3-D mission to save world, just don't tell them they are learning cell biology: Fri, 03 Feb 2012 08:10:02 EST - After growing up on an entertainment diet of X-Men and Xbox, high school and college-age students may find a textbook on cell biology to be a little, well, bland.
ASU, Berkeley researchers find cost to park is more than we think: Fri, 03 Feb 2012 08:10:01 EST - (PhysOrg.com) -- There’s no such thing as a free lunch, according to the old adage. And there’s no such thing as free parking, either.
Google loses appeal in Taiwan over app refund: Fri, 03 Feb 2012 06:40:01 EST - Taiwan said Friday it had rejected an appeal by Google against a fine imposed on the US Internet giant for refusing to grant customers a seven-day trial period on its mobile phone apps.
Japan's Panasonic set for $10.2 billion loss: Fri, 03 Feb 2012 06:20:01 EST - Japan's Panasonic on Friday warned it would see its worst-ever net loss of 780 billion yen ($10.2 billion) for the year to March, blaming the strong yen, flooding in Thailand, and acquisition costs.
Facebook's popularity also brings lawsuits: Fri, 03 Feb 2012 06:10:01 EST - As Facebook readies for Wall Street's richest high-tech debut, it is wrangling with litigation and bracing for potential new suits.
Megaupload boss' bail appeal 'rejected' in N.Z.: Fri, 03 Feb 2012 05:57:39 EST - Megaupload boss Kim Dotcom on Friday failed to overturn a ruling that he remain behind bars in New Zealand while US officials seek his extradition for alleged copyright piracy, reports said.
Pew study: Facebook users get more than they give: Fri, 03 Feb 2012 04:11:55 EST - (AP) -- The goody-two-shoes among us say it's better to give than to receive. That's not true for the average Facebook user, though.
Zuckerberg has iron grip on Facebook: Thu, 02 Feb 2012 19:50:01 EST - Facebook co-founder Mark Zuckerberg will retain an iron grip over the social network even after it becomes a public company.
After IPO, Facebook will face new profit pressures: Thu, 02 Feb 2012 18:16:25 EST - (AP) -- For all the huge numbers in Facebook's IPO papers, a surprisingly small figure stands out: $4.39, the amount the site generated per user last year.
'Like' Facebook stock? Experts weigh in on IPO: Thu, 02 Feb 2012 16:18:46 EST - (AP) -- Facebook's much-hyped initial public offering promises to be an exciting spectacle when the social media giant goes public this spring. But should you update your status to "shareholder"?

PHYSorg.com: Hi Tech & Innovation News

PhysOrg.com provides the latest news on hi-tech, innovation and new inventions technology, computer news and information

Fold-it computer action set for Canada conference (w/ video): Sat, 04 Feb 2012 06:00:01 EST - (PhysOrg.com) -- What nonsense, sitting in front of one, single display screen and struggling with a split-screen view of multiple-sites plus data entry or word processing. Is this the way it has to be for doing papers, writing reports, presenting detailed stats, and collaborating with others? In 2012, the single-screen sit-down is the common user experience, not nonsense, but a concept presentation at an upcoming conference in Canada could change expectations for good.
Darpa researchers design eye-enhancing virtual reality contact lenses: Wed, 01 Feb 2012 12:10:54 EST - Currently being developed by DARPA researchers at Washington-based Innovega iOptiks are contact lenses that enhance normal vision by allowing a wearer to view virtual and augmented reality images without the need for bulky apparatus.
Virtual Projection team puts iPhone writing on the wall (w/ video): Thu, 26 Jan 2012 05:30:01 EST - (PhysOrg.com) -- A collaborative team from the University of Calgary, University of Munich, and Columbia, have figured out a way to use a smartphone to project the phone’s display on to external displays nearby. The team thinks of its technology approach, Virtual Projection, as "borrowing available display space in the environment." Dominikus Baur, Sebastian Boring, and Steven Feiner are behind Virtual Projection. Feiner is Professor of Computer Science at Columbia University where he directs the Computer Graphics and User Interfaces Lab.
BMW shows hands-free driving on Autobahn (w/ video): Tue, 24 Jan 2012 05:10:01 EST - (PhysOrg.com) -- Move over, Google, or better still, stay off the Autobahn, best not to interfere with the main show, which now stars BMW and its technology feats with self-driving cars. BMW has been drawing press interest in its recent show of what will be possible in self-driving cars 10 to 15 years from now. BMW had announced in August its “ConnectedDrive Connect (CDC) system. This week, a video was released showing a BMW on CDC realtime. BMW put it on the Autobahn, along with a human driver who nonetheless kept hands off the wheel of the car, a BMW 5 series model.
OrcaM is new kid on block for 3-D data capture: Sat, 21 Jan 2012 06:50:01 EST - (PhysOrg.com) -- Call it automated photograph station, seven-camera system, 3-D model showcase, or digital reconstruction tool. OrcaM is being described as all these things. Whatever the tag, the "OrcaM" name stands for Orbital Camera System, according to its Germany-based developers NEK GmbH. A video demo was making the rounds of web gadget blogs and news sites this week as a camera system to watch.
BASF, Philips develop OLED lighting for use as transparent car roof: Thu, 19 Jan 2012 06:55:15 EST - (PhysOrg.com) -- BASF and Philips have achieved a practical breakthrough in the development of OLED (Organic Light Emitting Diode) technology that allows it to be integrated in car roofs. The OLEDs are transparent when switched off, allowing for a clear view outside the vehicle, yet providing light only within the vehicle when switched on. This OLED lighting concept for car roofs is the result of a longstanding cooperation between BASF and Philips in the research and development of OLED modules.
MIT lab working on wristband to allow for individual control of local building environment: Tue, 17 Jan 2012 12:00:01 EST - (PhysOrg.com) -- MIT Media Lab has announced that a team of researchers working in the Responsive Environments Group is hard at it trying to come up with just the right sort of wrist bracelet that could interface with a building fitted with sensors, to allow a user to easily alter the temperature, lighting or perhaps even the humidity levels of their immediate environment. Such a bracelet would also quite naturally also be used to alert other devices with motion detectors to become active.
Mercedes demos DICE -- Interactive dashboard and Heads-Up display: Tue, 17 Jan 2012 08:50:01 EST - (PhysOrg.com) -- High end car maker Mercedes-Benz last week demoed new technology it’s working on for future car dashboards and windshield displays, and the result is certainly eye opening. Called the Dynamic and Intuitive Control Experience (DICE), the system is a combination of a multitude of different technologies.
Bum's the word in Japan security scans: Tue, 17 Jan 2012 04:38:07 EST - Put your fingerprint scanners away. Stand aside iris measurers. Buttocks are the new way to prove who you are.
Ford collaborates with Microsoft for in-car health and wellness research: Thu, 12 Jan 2012 14:10:34 EST - Ford, Microsoft Corp. and Healthrageous are researching how connected devices can help people monitor and maintain health and wellness
User interface revolution coming to computers, TVs: Thu, 12 Jan 2012 07:30:02 EST - Control your television with your voice or a wave of the hand. Run your laptop with your eyes.
Automakers embrace high-tech in safety drive: Wed, 11 Jan 2012 08:45:15 EST - Automakers displaying the latest technology at the Consumer Electronics Show (CES) are relying on sensors, digital cameras and connectivity in a drive towards a common goal -- eliminating accidents.
Austin lab team rolls out Kinect-controlled skateboard: Tue, 10 Jan 2012 13:50:01 EST - (PhysOrg.com) -- An Austin, Texas, team has developed an electric skateboard that makes use of Microsoft’s Kinect and a Samsung tablet running Windows 8 to go places on a piece of transport dubbed The Board of Awesomeness. Scheduled for showing at the CES show in Las Vegas, the board teams up with the Windows 8 Samsung tablet and Kinect controller. The smartened-up device has capabilities that include combined video and speech recognition location and accelerometer data.
New smart e-book system more convenient than paper-based books: Tue, 10 Jan 2012 10:40:03 EST - Korea Advanced Institute of Science and Technology (KAIST) announced today that its research team headed by Professor Howon Lee from the IT Convergence Research Institute has developed a technology that will make reading on smartphones and tablet PCs easier than now.
Apple patent sends password secrets to adapters: Fri, 06 Jan 2012 11:45:21 EST - (PhysOrg.com) -- First-time computer users in the early days, pre-hacking security traumas, were confronted with a new life requirement: creating and remembering system passwords. Not too easy, users were warned, to protect their privacy against snooping brothers and sisters, but not too tough, so they can easily remember it all times. This is no longer good advice, and Apple has filed a patent that says, no, make your password as tough as you want.
Japan plans futuristic farm in disaster zone: Thu, 05 Jan 2012 04:50:02 EST - Japan is planning a futuristic farm where robots do the lifting in an experimental project on land swamped by the March tsunami, the government said Thursday.
India army offers 'glacier toilet' in hi-tech sell-off: Tue, 03 Jan 2012 03:10:01 EST - Developed for troops serving on glaciers high in the Himalayas, the non-flushing "bio-digester" toilet made by India's top defence research body is now being offered to companies and poorer states.
Greying Singapore taps robots, games in rehab: Sun, 01 Jan 2012 06:33:55 EST - Six months ago, Singaporean retiree Soon Eng Sam, 70, suffered a stroke that paralysed the left side of his body.
Cotton computing goes live at Cornell textiles lab: Fri, 30 Dec 2011 12:10:28 EST - (PhysOrg.com) -- Researchers from France, Italy and the United States are weaving cotton with transistors for a new look in computing. Based on news about a lab at Cornell University, wearable computing is getting a new twist. Transistors made from cotton fibers are being explored at the Textiles Nanotechnology Laboratory at Cornell for use as clothing to collect, monitor and relay information.
Researchers hope to use bugged bugs for search and rescue: Thu, 29 Dec 2011 13:18:14 EST - (PhysOrg.com) -- While search and rescue dogs are currently used to help locate survivors of earthquakes or other disasters, new research hopes to make this job easier by turning to bugs. Insects have the ability to get into the smallest of places and could make locating people that much easier.
MIT student builds self-balancing electric unicycle: Thu, 29 Dec 2011 08:50:01 EST - (PhysOrg.com) -- If ever you go look outside at all the traffic on the road, it's hard to not come to the conclusion that what’s needed is a smaller vehicle; perhaps one that doesn’t take up any more room than the body that it needs to transport. The Segway is a good example, though it does take up more ground space than a person simply standing. Lucky thing we have smart people like Stephan Boyer, a student at MIT who has created an electric unicycle that not only does some self-stabilizing, but is an actual functioning vehicle which he uses to get himself around the school campus.
Holographic 3-D looks tantalizingly closer in 2012: Wed, 28 Dec 2011 11:40:15 EST - (PhysOrg.com) -- Applications like holographic TV have long been relegated as the next big thing in the distant future but a Leuven, Belgium-based R&D lab for nanoelectronics has come up with a process that might bring holographic images closer to realtime.
Kraft uses Intel technology in vending machine to target customers by age: Tue, 27 Dec 2011 09:30:01 EST - (PhysOrg.com) -- In a clever mix of technology and marketing, Kraft Foods has teamed up with Intel to create a vending machine, called the iSample, that can dispense free pudding samples to adults only; it’s intended target audience for its new product. The result is a machine currently in place at the Shedd Aquarium in Chicago. Patrons who approach the machine are scanned, and if deemed old enough, are urged to use their smart phone to type in or swipe a code that then allows the assumed grown-up to pick a flavor, which is then dropped down for them to grab and eat. All for free. If a kid tries to do the same, they are denied a free sample and asked to step aside so that a deserving adult can get a treat.
No-glasses 3-D technology to showcase at CES 2012: Mon, 26 Dec 2011 06:30:01 EST - (PhysOrg.com) -- Stream TV Networks plans to introduce a line of products that feature 3-D viewing without glasses. What’s so special about its announcement, on top of scores of 3-D-without-glasses announcements? The company says it has special technology in the name of Ultra-D, which can do nothing less than shift the way people will view media, according to its CEO.
Engineers unleash car-seat identifier that reads your rear end: Sun, 25 Dec 2011 06:20:01 EST - (PhysOrg.com) -- Cars of the future may use the driver’s rear end as identity protection, through a system developed at Japan’s Advanced Institute of Industrial Technology. A report surfaced earlier this month that researchers there developed a system that can recognize a person by the backside when the person takes a seat. The system performs a precise measurement of the person’s posterior, its contours and the way the person applies pressure on the seat. The developers say that in lab tests, the system was able to recognize people with 98 percent accuracy.
Data to be a defining tech trend in 2012: Sat, 24 Dec 2011 05:50:23 EST - The start of this year was marked by a tech industry obsession with where to put growing mountains of information gathered online and by sensors increasingly woven into modern lifestyles.
Hollywood still struggling to focus 3D technology: Wed, 21 Dec 2011 04:40:31 EST - Two years after breakthrough 3D megahit "Avatar," Hollywood is still struggling to decide how best to use the new technology, as filmgoers tire of the novelty and say no to annoying glasses.
Mind reading machines on their way: IBM: Tue, 20 Dec 2011 04:54:47 EST - Century-old technology colossus IBM depicted a near future in which machines read minds and recognize who they are dealing with.
IBM reveals five innovations that will change our lives in the next five years (Update): Mon, 19 Dec 2011 09:13:38 EST - Today IBM formally unveiled the sixth annual “IBM 5 in 5" (#ibm5in5) – a list of innovations that have the potential to change the way people work, live and interact during the next five years.
Military looks for more 'fear factor' in training simulators: Thu, 15 Dec 2011 17:50:01 EST - The group of Marines sprang into action and raced into combat position, with weapons aimed, as they assaulted a possible terrorist stronghold. Moments later, they were sipping sodas and chatting with friends about weekend plans.

TrendHunter.com - Science and Discovery

Science and Discovery

Rusty Auto Murals - Bo Lundvang Creates Oxidized Pop Art Featuring Popular Cars (TrendHunter.com): Sun, 05 Feb 2012 09:34:03 GMT - (TrendHunter.com) Bo Lundvang has found an interesting way to use rust in his artwork. The Swedish artist, who is also a writer for the car magazine Bilsport (and has been labeled a "media polymath"), has created as series...
Scientifically Evaluating Motivation - Daniel Pink Compares Intrinsic Versus Extrinsic Motives (TrendHunter.com): Sat, 04 Feb 2012 20:04:05 GMT - (TrendHunter.com) Career analyst, author and journalist Daniel Pink makes a case for long overdue change in the working world in what he calls “the surprising science of motivation,” based on the disjunction between what...
The Science of Scent - Luca Turin Discusses the Chemical Makeup of Fragrances (TrendHunter.com): Fri, 03 Feb 2012 21:17:03 GMT - (TrendHunter.com) Luca Turin, biophysicist and author of 'Perfumes: The Guide' examines the molecular makeup and the artful execution of a scent. Employing an immense sense of precision and intricate combinations, Turin...
Mangled Anatomical Architecture - Primal Parts by Kyd Kitchaiya Explores the Biology of Building (TrendHunter.com): Fri, 03 Feb 2012 20:06:02 GMT - (TrendHunter.com) It's a little unsettling to view this project called Primal Parts by Kyd Kitchaiya. Would it surprise you to learn that the designer's family are pig butchers? Probably not. But what is so admirable about...
Wearable Muscle Stimulators - The Elektrodress Helps Individuals Suffering From Nerve Disorders (TrendHunter.com): Fri, 03 Feb 2012 11:06:05 GMT - (TrendHunter.com) With his 'Elektrodress' creation, inventor and doctor Fredrik Lundqvist is changing the way scientists and doctors look at neurology and rehabilitation when it comes to nerve disorders. The Elektrodress...
Ocean Tracking Apps - The Expedition White Shark App for iPhone Brings Shark Week to Your Pocket (TrendHunter.com): Thu, 02 Feb 2012 20:18:03 GMT - (TrendHunter.com) The Expedition White Shark app for iPhone, iPad and iPod is the awesome product of the Marine Conservation Science Institute that lets you track white sharks as they swim in the sea from the palm of your...
Miniature Future Fighter Jets - Autonomous Nano Quadrotors are the Most Futuristic Invention Yet (TrendHunter.com): Thu, 02 Feb 2012 18:37:03 GMT - (TrendHunter.com) The GRASP Lab at the University of Pennsylvania has developed autonomous quadrotors; what seem to be replicas of the airborne Decepticons from the most recent Transformers movie. These little flying machines...
Phytoplankton-Inspired Pavilions - The Cocoon_FS is a Portable Structure for PlanktonTech (TrendHunter.com): Wed, 01 Feb 2012 23:29:05 GMT - (TrendHunter.com) The Cocoon_FS pavilion is inspired by a type of phytoplankton called diatoms. Built for the PlanktonTech organization, a German research institution that studies plankton, this unique structure represents...
Crack-Detecting Paint - Researchers Develop Coloring that Locates Damage in Bridges (TrendHunter.com): Wed, 01 Feb 2012 06:52:03 GMT - (TrendHunter.com) When not properly maintained or inspected, a bridge can be extremely dangerous to those who use it, but now a group of University of Strathclyde engineers have created a crack-detecting paint that can...
Mood-Sensing Autos - The RThropod Concept Car Connects on a Genetic Level with Drivers (TrendHunter.com): Sat, 28 Jan 2012 06:09:02 GMT - (TrendHunter.com) Lucas Lopez has designed a game-changing car: the RThropod concept car. This vehicle would actually link its owners genetically to their car! Designed by the Argentine, the RThropod concept car would actually...
Pollution-Fighting Cleansers - The World's First Magnetic Soap Can Clean Oil Spills Faster (TrendHunter.com): Fri, 27 Jan 2012 07:15:03 GMT - (TrendHunter.com) Scientists from the University of Bristol have developed the world's first magnetic soap by embedding iron into chemicals found in mouthwash and fabric conditioner. The soap was tested to see if it would...
Vibrating Energy Structures - The Vibro-Wind Piezoelectric Pads are Eco-Friendly (TrendHunter.com): Thu, 26 Jan 2012 19:19:02 GMT - (TrendHunter.com) The Vibro-Wind Piezoelectric Pads now provide a more eco-friendly form of electricity. Critics held that wind turbines took up too much space, were too noisy and presented harm to winged animals such as...
Photography Beauty Brand Extensions - Fujifilm Launches Astalift Skincare Line in Western Markets (TrendHunter.com): Thu, 26 Jan 2012 12:26:03 GMT - (TrendHunter.com) Fujifilm recently ventured into the world of beauty with its new Astalift skincare line, which was introduced in the Japanese and Chinese markets in late 2011. Now, the Astalift skincare brand will be...
Ballooning Portable Planetariums - The Inflativerse Offers a View of Space in No Time at All (TrendHunter.com): Thu, 26 Jan 2012 04:52:03 GMT - (TrendHunter.com) Space and time may be intrinsically related but the tight relationship is rarely as apparent as it is demonstrated by the Inflativerse. The blow-up dome is a mobile Starlab planetarium, bringing the wisdom...
Translucent Solar Windows - The Lightfarm Collects Energy and Looks Appealing (TrendHunter.com): Thu, 26 Jan 2012 03:12:03 GMT - (TrendHunter.com) The 'Lightfarm' aims to integrate concentrated solar technology in a building's facade, and to supply major energy consumption by installing hybrid CPV modules on buildings. CPV modules have been proven...
Intoxication-Inhibiting Drugs - Dhm May Be the Cure for Alcoholism (TrendHunter.com): Wed, 25 Jan 2012 21:04:03 GMT - (TrendHunter.com) The latest and greatest output of the scientific community is the potential alcohol cure called DHM. This drug is found in a Chinese raisin tree and has been used in China to treat hangovers for over 500...
Virtual Pandemic Treatment - David Eagleman Explains How the Internet Can Help Save Civilization (TrendHunter.com): Wed, 25 Jan 2012 07:45:02 GMT - (TrendHunter.com) In this speech, neuroscientist and bestselling author David Eagleman discusses three reasons why the Internet will play a significant role in ensuring the survival of civilization. David Eagleman strongly...
Liquid-Testing Lasers - The Cobalt Insight100 Could Change Airport Security Measures (TrendHunter.com): Wed, 25 Jan 2012 01:02:03 GMT - (TrendHunter.com) The Cobalt Insight100 is a new laser scanner capable of detecting explosive chemicals in liquids and gels by firing a laser into the bottle, and then measuring the light as it bounces back. Since every...
Vivid Space Storm Recordings - The NASA 'ISS Passes Over Stormy Africa' Video is Mesmerizing (TrendHunter.com): Mon, 23 Jan 2012 18:29:31 GMT - (TrendHunter.com) Orbiting the world are many, many satellites -- not all of which will be broadcasting the Superbowl -- and one of them has captured some cosmic lightning, which is documented in a video called 'ISS Passes...
Communities on the Moon - Kirk Sorensen Shares the Self-Sustaining Properties and Perks of Thorium (TrendHunter.com): Fri, 20 Jan 2012 10:20:17 GMT - (TrendHunter.com) In this speech, Kirk Sorensen explains how he stumbled across a naturally occurring fuel in the earth's surface that he believes could enable individuals to create a self-sustaining community on the moon....
Mind-Reading Armbands - BodyWave Technology at CES 2012 is Mind-Control Without a Headset (TrendHunter.com): Tue, 17 Jan 2012 05:31:02 GMT - (TrendHunter.com) Another leap in mind-reading has been taken by Freer Logic with BodyWave technology at CES 2012. This is the first time, mind reading and mind control has been made possible without the use of an unattractive...
Insect-Based Material Alternatives - Cheryl Hayashi Shares Spider Silk's Potential Future Uses (TrendHunter.com): Mon, 16 Jan 2012 22:43:10 GMT - (TrendHunter.com) In this speech, biologist Cheryl Hayashi discusses how much the world's populations can learn from spiders. She begins her speech by stating that spiders can be found in nearly every terrestrial habitat...
Non-Invasive Surgery - Yoav Medon Shows How Focused Ultrasound Can Lead to More Effective Procedures (TrendHunter.com): Mon, 16 Jan 2012 21:20:03 GMT - (TrendHunter.com) In this medical-related speech, Yoav Medan discusses new technologies that enable doctors to perform medical procedures without having to make invasive incisions. Yoav Medan and his team of scientists,...
Solar System Chocolates - Japanese Chocolate Makers 'L'eclat' Create Out-of-This-World Treats (TrendHunter.com): Mon, 16 Jan 2012 16:52:03 GMT - (TrendHunter.com) If you've ever wondered what Saturn tastes like you can now find out because, according to Japanese chocolate makers L'éclat, it tastes suspiciously like rum and raisin. For $50 you can get your hands...
Fierce Futuristic Fashionistas - Tejal Patni Creates a World of Tomorrow in This Splash Calendar (TrendHunter.com): Mon, 16 Jan 2012 14:12:02 GMT - (TrendHunter.com) This fashion editorial by photographer Tejal Patni offers an imaginative look into the decades to come and illustrates what living on another planet in the future may resemble. Because this year could...
Preparing for Pandemics - Laurie Garrett Offers Insight into Effectively Coping with Global Disease (TrendHunter.com): Sun, 15 Jan 2012 07:56:03 GMT - (TrendHunter.com) Laurie Garrett is one of the world's leading experts on global healthcare and pandemics. In this powerful speech, she discusses possible global spread of the 'bird flu,' also known as the H5N1 flu. Laurie...
The Mathematics of War - Sean Gourley Reveals a Startling Pattern in Today's Most Fatal Conflicts (TrendHunter.com): Sun, 15 Jan 2012 05:06:02 GMT - (TrendHunter.com) In this speech, physicist Sean Gourley explains how he has merged the study of mathematics, namely probability, with politics and war. Startled by the number of conflicts and high death tolls plaguing...
Early Linguistic Development - Patricia Kuhl Shows How a Baby's Brain Categorizes Complex Languages (TrendHunter.com): Sat, 14 Jan 2012 22:43:02 GMT - (TrendHunter.com) In this speech, Patricia Kuhl discusses early language and brain development in babies. She describes babies as geniuses when it comes to learning a new language. As she explains, babies are capable of...
Transforming Trash into Toys - Arvind Gutpa Shares His Educational Designs Made Using Garbage (TrendHunter.com): Sat, 14 Jan 2012 00:11:02 GMT - (TrendHunter.com) In this speech, educator and innovator Arvind Gupta demos the educational toys he creates for children using the most basic of materials, including garbage. With a background in design and the motivation...
31 Killer Detroit Auto Show Debuts - Super-tuned Muscle Electrified Gull Wing Rides (TrendHunter.com): Fri, 13 Jan 2012 10:07:02 GMT - (TrendHunter.com) Pump yourself up for the awesomeness that is the first American motor show of the year by checking out all of these killer Detroit Auto Show debuts. The 2012 Detroit Auto Show is in full swing, and automakers...

NaviGadget

GPS Navigation Systems, GPS Tracking Devices, GPS Phones, Receivers, Reviews, and Hacks

LightSquared and GPS community have no solution: Sat, 04 Feb 2012 19:31:10 +0000 - We’ve been talking about the battle between LightSquared and the GPS industry. The heart of the problem is that the spectrum for 4G network and the GPS signals are right next to each other and compared to GPS signals 4G signals are way way stronger, possibly causing interference. In a report published June last year [...]
Brought to you by your GPS navigation site NaviGadget.

LightSquared and GPS community have no solution
new GPS module from Fastrax promises less battery drain and quicker satellite fix: Fri, 03 Feb 2012 19:24:14 +0000 - Fastrax just introduced the Fastrax IT530, an ultra-low power and super-sensitive OEM GPS module. As far as specs this tiny location finding unit has sensitivity of -148 dBm in acquisition, -165 dBm in navigation, and power consumption of 35 mW at 3.3 V. It measures and weighs pretty much nothing with dimensions of 9.6 x [...]
Brought to you by your GPS navigation site NaviGadget.

new GPS module from Fastrax promises less battery drain and quicker satellite fix
Suunto AMBIT GPS watch: Fri, 03 Feb 2012 16:47:27 +0000 - Suunto just recently announced the launch of the AMBIT, a GPS watch for Explorers. Why Ambit? Their press release says *AMBIT: As in Ambition. Synonyms: edge, reach, scope or range. OK, whatever, moving on. What you get with this GPS watch is a GPS navigation system, barometer, altimeter, 3D compass, and more. It has a [...]
Brought to you by your GPS navigation site NaviGadget.

Suunto AMBIT GPS watch
Supreme Court says warrentless GPS tracking is against 4th amendment: Tue, 31 Jan 2012 03:55:03 +0000 - Supreme Court decided earlier this month that police officers violated the Fourth Amendment which protects citizens against unreasonable search and seizure. The law enforcement attached a GPS tracking device to a suspect’s vehicle and tracked it for a month without a warrant. Even though the ruling was unanimous the reasoning was split in two. some [...]
Brought to you by your GPS navigation site NaviGadget.

Supreme Court says warrentless GPS tracking is against 4th amendment
FujiFilm FinePix F770EXR with GPS: Fri, 27 Jan 2012 04:51:24 +0000 - Fujifilm just recently introduced the FinePix F770EXR which will be available in March 2012 for $380. The most outstanding feature for us is of course the GPS capabilities of this camera. In addition F770EXR features 16MP EXR-CMOS, 20x optical zoom, 1.5 seconds start up time, and 1 second between shots. As far as the GPS [...]
Brought to you by your GPS navigation site NaviGadget.

FujiFilm FinePix F770EXR with GPS
TomTom to power Samsung’s Wave 3 Bada Maps: Thu, 26 Jan 2012 02:21:37 +0000 - TomTom made a deal with Samsung where TomTom maps will power Samsung Wave3. With this agreement Samsung Wave 3 Bada gets: Map coverage for 200+ countries which equals to 35 million kilometers roads Points of interests on these maps 3D City Maps and 3D Landmarks Traffic updates Speed Cameras alerts Brought to you by your [...]
Brought to you by your GPS navigation site NaviGadget.

TomTom to power Samsung’s Wave 3 Bada Maps
Alpine INE-Z928HD and INE-S920HD: Wed, 25 Jan 2012 04:43:18 +0000 - Alpine Electronics introduced the biggest after market in-dash GPS/audio/video system available called Alpine INE-Z928HD with a 8″ screen and a $1500 price tag. It also announced Alpine INE-S920HD with a 6.1″ screen which is going to cost $1000. Here are some of the highlights INE-Z928HD and INE-S920HD free lifetime NAVTEQ Traffic RDS (Z928HD) HD Radio [...]
Brought to you by your GPS navigation site NaviGadget.

Alpine INE-Z928HD and INE-S920HD
BMW does something more useful with that map data: Tue, 24 Jan 2012 04:01:02 +0000 - The new ActiveHybrid 3 series will feature a system that can predict the best time to charge its batteries. Since the navigation map data includes hill profiles, and the car knows the direction you’re headed this means fuel efficiency. Say you’re about to go uphill for a while and then descend back down hill. Your [...]
Brought to you by your GPS navigation site NaviGadget.

BMW does something more useful with that map data
TomTom GPS navigation line-up for 2012: Tue, 24 Jan 2012 03:47:12 +0000 - TomTom earlier this month introduced three new lines to their products. These are TomTom START, TomTom VIA, and TomTom GO LIVE. Here’s the summary really: TomTom START: Pretty basic, budget devices that get the job done. Lifetime traffic and map updates Speaks street names Fuel prices TomTom VIA: Have more money to spend? Get this. [...]
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TomTom GPS navigation line-up for 2012
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PHYSorg.com: Physics News

Physorg.com provides the latest news on physics, materials, nanotech, science and technology. Updated Daily.

Crystalline materials enable high-speed electronic function in optical fibers: Sun, 05 Feb 2012 13:00:07 EST - Scientists at the University of Southampton, in collaboration with Penn State University have, for the first time, embedded the high level of performance normally associated with chip-based semiconductors into an optical fibre, creating high-speed optoelectronic function.
Renowned physicist invents microscope that can peer at living brain cells: Fri, 03 Feb 2012 09:50:01 EST - (PhysOrg.com) -- Ever since scientists began studying the brain, they’ve wanted to get a better look at what was going on. Researchers have poked and prodded and looked at dead cells under electron microscopes, but never before have they been able to get high resolution microscopic views of actual living brain cells as they function inside of a living animal. Now, thanks to work by physicist Stefan Hell and his colleagues at the Max Planck Institute in Germany, that dream is realized. In a paper published in Science, Hell and his team describe the workings of their marvelous discovery.
Searching for a solid that flows like a liquid: Fri, 03 Feb 2012 09:10:01 EST - (PhysOrg.com) -- A series of neutron scattering experiments at Oak Ridge National Laboratory and other research centers is exploring the key question about a long-sought quantum state of matter called supersolidity: Does it exist?
Optics get magnetic powers: Fri, 03 Feb 2012 08:50:01 EST - For decades, scientists have studied a class of materials called ‘multiferroics’ in which static electric and magnetic structures are coupled to each other. This allows capabilities such as controlling magnetic order with electric fields instead of magnetic ones, making it easier to build devices such as sensors and computer memory.
Manipulating the texture of magnetism: Fri, 03 Feb 2012 08:30:02 EST - Knowing how to control the combined magnetic properties of interacting electrons will provide the basis to develop an important tool for advancing spintronics: a technology that aims to harness these properties for computation and communication. As a crucial first step, Naoto Nagaosa from the RIKEN Advanced Science Institute, Wako, and his colleagues have derived the equations that govern the motion of these magnetic quasi-particles.
Size matters -- even for molecules: Fri, 03 Feb 2012 07:45:36 EST - (PhysOrg.com) -- Two electrons that are emitted from a large molecule by a single photon may originate from far apart within that molecule. In a recent study on hydrocarbon molecules consisting of one to five fused benzene rings (each ring consisting of six carbon atoms), Synchrotron Radiation Center researchers Tim Hartman and Ralf Wehlitz have found that the relative probability for ejecting two electrons scales linearly with the length of the molecule.
New kind of high-temperature photonic crystal could someday power everything from smartphones to spacecraft: Fri, 03 Feb 2012 06:19:30 EST - A team of MIT researchers has developed a way of making a high-temperature version of a kind of materials called photonic crystals, using metals such as tungsten or tantalum. The new materials — which can operate at temperatures up to 1200 degrees Celsius — could find a wide variety of applications powering portable electronic devices, spacecraft to probe deep space, and new infrared light emitters that could be used as chemical detectors and sensors.
Physicists push for underground testing facility: Thu, 02 Feb 2012 09:40:01 EST - Pran Nath, the Matthews Distinguished Professor of Physics at Northeastern University, is among a group of leading theoretical physicists who have asked the Department of Energy to develop a large underground neutrino facility to maintain U.S. leadership in the frontier of particle physics. We asked Nath to explain the facility and its value.
Magnetic random-access memory based on new spin transfer technology achieves higher storage density: Thu, 02 Feb 2012 08:21:19 EST - Solid-state memory is seeing an increase in demand due to the emergence of portable devices such as tablet computers and smart phones. Spin-transfer torque magnetoresistive random-access memory (STT-MRAM) is a new type of solid-state memory that uses electrical currents to read and write data that are stored on magnetic moment of electrons. Rachid Sbiaa and co-workers at the A*STAR Data Storage Institute have now enhanced the storage density of STT-MRAM by packing multiple bits of information into each of its memory cells.
Want to understand the fluid dynamics of the oceans and atmosphere? UCLA's got the video: Thu, 02 Feb 2012 08:19:23 EST - (PhysOrg.com) -- Oceans and clouds, even the atmosphere itself, are in constant motion and can undergo dramatic fluctuations, like hurricanes, that lead to severe consequences. If you've ever wondered how these enormous systems function, wonder no longer.
Researchers efficiently couple light from a plane wave into a surface plasmon mode: Thu, 02 Feb 2012 08:10:01 EST - Researchers from the NIST Center for Nanoscale Science and Technology have made a grating coupler that transmits over 45 % of the incident optical energy from a plane wave into a single surface plasmon polariton (SPP) mode propagating on a flat gold surface, an order-of-magnitude increase over any SPP grating coupler reported to date.
Powering pacemakers with heartbeat vibrations: Wed, 01 Feb 2012 17:00:24 EST - Sick hearts may help to keep themselves beating longer with a device that could harvest energy from heartbeat-induced chest cavity vibrations.
Building a better light bulb: Wed, 01 Feb 2012 16:59:53 EST - Scientists study the movement of charge carriers to design an organic LED that is energy efficient and still casts a warm, natural glow.
Precision time: A matter of atoms, clocks, and statistics: Wed, 01 Feb 2012 16:57:52 EST - Time is of the essence, especially in communications, navigation, and electric power distribution, which all demand nanosecond precision or better. Keeping these beating hearts of technology in near-perfect global synchronization requires the blending of statistics, atomic science, and technological innovations.
Polarization imaging: Seeing through the fog of war: Wed, 01 Feb 2012 13:17:21 EST - Funded by the Air Force Office of Scientific Research, the development of a new circular polarization filter by a collaborative team of scientists at the Colorado School of Mines and ITN Energy Systems has the potential to aid in early cancer detection, enhance vision through dust and clouds and to even improve a moviegoer's 3D experience.
Brain capacity limits exponential online data growth: Wed, 01 Feb 2012 13:01:46 EST - Scientists have found that the capacity of the human brain to process and record information - and not economic constraints - may constitute the dominant limiting factor for the overall growth of globally stored information. These findings have just been published in an article in EPJ B by Claudius Gros and colleagues from the Institute for Theoretical Physics at Goethe University Frankfurt in Germany.
Physicists create first 'frequency comb' to probe ultraviolet wavelengths: Wed, 01 Feb 2012 13:00:07 EST - Physicists at JILA have created the first "frequency comb" in the extreme ultraviolet band of the spectrum, high-energy light less than 100 nanometers (nm) in wavelength. Laser-generated frequency combs are the most accurate method available for precisely measuring frequencies, or colors, of light. In reaching the new band of the spectrum, the JILA experiments demonstrated for the first time a very fine mini-comb-like structure within each subunit, or harmonic, of the larger comb, drastically sharpening the measurement tool.
Researchers at SLAC test collider closer to creating fully coherent X-rays: Wed, 01 Feb 2012 11:09:33 EST - (PhysOrg.com) -- Many advanced laser technologies, such as laser spectroscopy, that use precise wavelengths of infrared, visible or ultraviolet laser light could benefit from using X-ray light as well. But to reach its full potential, that X-ray light must be just as coherent as the light from the optical lasers now in use – a requirement beyond current X-ray laser technology.
Repulsive gravity as an alternative to dark energy (Part 2: In the quantum vacuum): Wed, 01 Feb 2012 10:00:01 EST - (PhysOrg.com) -- During the past few years, CERN physicist Dragan Hajdukovic has been investigating what he thinks may be a widely overlooked part of the cosmos: the quantum vacuum. He suggests that the quantum vacuum has a gravitational charge stemming from the gravitational repulsion of virtual particles and antiparticles. Previously, he has theoretically shown that this repulsive gravity can explain several observations, including effects usually attributed to dark matter. Additionally, this additional gravity suggests that we live in a cyclic Universe (with no Big Bang) and may provide insight into the nature of black holes and an estimate of the neutrino mass. In his most recent paper, published in Astrophysics and Space Science, he shows that the quantum vacuum could explain one more observation: the Universe’s accelerating expansion, without the need for dark energy.
Shaken, not heated: The ideal recipe for manipulating magnetism: Wed, 01 Feb 2012 04:30:39 EST - (PhysOrg.com) -- Scientists have found a way to distort the atomic arrangement and change the magnetic properties of an important class of electronic materials with ultra-short pulses of terahertz (mid-infrared) laser light without heating the material up. While the achievement is currently of purely scientific interest, the researchers say this new approach control could ultimately lead to extremely fast, low-energy, non-volatile computer memory chips or data-switching devices.
The future of Fermilab: Tue, 31 Jan 2012 19:00:10 EST - In this month's Physics World, reviews and careers editor, Margaret Harris, visits the Fermi National Accelerator Laboratory (Fermilab) to explore what future projects are in the pipeline now that the Tevatron particle accelerator has closed for good.
Repulsive gravity as an alternative to dark energy (Part 1: In voids): Tue, 31 Jan 2012 11:19:17 EST - (PhysOrg.com) -- When scientists discovered in 1998 that the Universe is expanding at an accelerating rate, the possibility that dark energy could explain the observation was intriguing. But because there has been little progress in figuring out exactly what dark energy is, the idea has since become more of a problem than a solution for some scientists. One physicist, Massimo Villata of the National Institute for Astrophysics (INAF) in Pino Torinese, Italy, describes dark energy as “embarrassing,” saying that the concept is an ad hoc element to standard cosmology and is devoid of any physical meaning. Villata is one of many scientists who are looking for new explanations of the Universe’s accelerating expansion that involve some form of repulsive gravity. In this case, the repulsive gravity could stem from antimatter hiding in voids.
Ferroelectric switching discovered for first time in soft biological tissue: Mon, 30 Jan 2012 16:37:02 EST - The heart's inner workings are mysterious, perhaps even more so with a new finding. Engineers at the University of Washington have discovered an electrical property in arteries not seen before in mammalian tissues.
Many bodies make one coherent burst of light: Researchers see superfluorescence from solid-state material: Mon, 30 Jan 2012 16:13:37 EST - In a flash, the world changed for Tim Noe – and for physicists who study what they call many-body problems. The Rice University graduate student was the first to see, in the summer of 2010, proof of a theory that solid-state materials are capable of producing an effect known as superfluorescence.
Oxygen molecule survives to enormously high pressures: Mon, 30 Jan 2012 11:05:46 EST - Using computer simulations, a Ruhr-University Bochum (Germany) researcher has shown that the oxygen molecule (O2) is stable up to pressures of 1.9 terapascal, which is about nineteen million times higher than atmosphere pressure. Above that, it polymerizes, i.e. builds larger molecules or structures.
Harnessing the predictive power of virtual communities: Mon, 30 Jan 2012 10:56:31 EST - Scientists have created a new algorithm to detect virtual communities, designed to match the needs of real-life social, biological or information networks detection better than with current attempts. The results of this study by Lovro Šubelj and his colleague Marko Bajec from the University of Ljubljana, Slovenia have just been published in European Physical Journal B.
A new discovery answers an old question: Mon, 30 Jan 2012 09:40:01 EST - (PhysOrg.com) -- The transition-metal monoxide FeO is an archetypal example of a Mott insulator—a material that should conduct electricity under conventional band theories but becomes an insulator when measured, especially at low temperatures—and a major iron-bearing component of the Earth’s interior. Understanding the high-pressure behavior of this material is important for both solid-state physics and Earth science. But despite considerable study over the past 30 years, the origin of the well-known high-pressure-induced cubic-rhombohedral ferroic transition in FeO, which is a distortion of the original cubic structure to that of as rhomboid shape, has been not well understood.
Discovery of 'bioelectric' arteries opens path to heart disease treatment: Mon, 30 Jan 2012 08:50:03 EST - Bionic eyes and limbs made television's six million dollar man an icon, but new research suggests our existing biological structure already exhibits a valuable electrical property. Scientists have found that arteries react curiously to external electric fields, opening the door to minimally invasive detection and treatment of the U.S.'s number one killer -- heart disease.
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers: Mon, 30 Jan 2012 08:50:01 EST - (PhysOrg.com) -- A wide range of phenomena depend on ice – specifically, phase transitions during ice crystal surface melting. In this transition, which occurs near the melting point, the ice surface morphs into what is known as a quasi-liquid layer (QLL) – a thin layer of ice grains where the water molecules are not in rigid solid structure, yet not in the random order of liquid. While previous research showed that QLL thickness increased with temperature, the results varied by as much as two orders of magnitude. Recently, however, scientists at Hokkaido University, in conjunction with Olympus Engineering Co., Ltd., developed a technique – laser confocal microscopy combined with differential interference contrast microscopy – that increases spatiotemporal resolution to point needed to visualize transition process of the 0.37nm (the thickness of one water molecule) step-like crystal surface at 0.1 – 4 seconds per frame. Their findings provide molecular-level understanding of QLLs that has implications for many QLL-dependent applications, including skating rink slipperiness, regelation (pressure-induced change in freezing), ice column frost heave, recrystallization and coarsening of ice grains, morphological change of snow crystals, cryopreservation, and electrification of thunderclouds.
Quantum physicists shed new light on relation between entanglement and nonlocality: Mon, 30 Jan 2012 06:17:50 EST - (PhysOrg.com) -- New research from the University of Bristol may disprove a long-standing conjecture made by one of the founders of quantum information science: that quantum states featuring ‘positive partial transpose’, a particular symmetry under time-reversal, can never lead to nonlocality.

ScienCentral

Making Sense of Science

ScienCentral was bought by MP Axle, Inc.: Thu, 19 May 2011 20:23:08 +0000 - ScienCentral still makes sense of science, but under new ownership. Please be sure to contact us at our new address: 1329 Tulane Rd Wilmington, DE 19803 718-432-5375 sciencentral at mpaxle dot com
ScienCentral has a new owner: Thu, 19 May 2011 20:21:34 +0000 - Same ability to make sense of science - new address and phone number. 1329 Tulane Rd Wilmington, DE 19803 718-432-5375 sciencentral at mpaxle dot com
Hawaiian Heat: Tue, 13 Oct 2009 00:00:00 +0000 - With climate change forecasts calling for tough times in tropical climates, scientists in America’s tropical paradise of Hawaii are carefully monitoring nature for signs of change, and citizen scientists are helping them find those signs in the ocean’s coral reefs.
2009 Benjamin Franklin Medal Winner: Lotfi A. Zadeh: Wed, 07 Oct 2009 00:00:00 +0000 - The 2009 Benjamin Franklin Medal in Electrical Engineering is presented to Lotfi Zadeh for his invention and development of the field of fuzzy logic, a mathematical system that captures aspects of the ambiguity of human language and thought, which has solved problems in areas such as artificial intelligence and the automated control of machines.
Naps and Creativity: Wed, 30 Sep 2009 00:00:00 +0000 - Telling your boss you need a nap might not be the smartest thing to do at work, but scientific evidence is now on your side. As this ScienCentral News video explains, sleep researchers just released a new study that says naps over an hour long may boost creative problem solving.
Street Corner Science with Stephen Benkovic: Wed, 23 Sep 2009 00:00:00 +0000 - ScienCentral is taking science back to the people with our second installment of "Street Corner Science," the radical yet-simple concept in which a film crew and a renowned scientist are plunked down amidst a busy city center, and an impromptu Q&A session with the public ensues.
Girls Vs. Boys at Math: Fri, 11 Sep 2009 00:00:00 +0000 - Are men naturally better at math than women or is that just an out-dated stereotype? When former Harvard president Larry Summers said publicly in 2005 that men are innately better at math, many women were outraged. So a couple of women scientists decided to research it. This ScienCentral News video explains their report published this week.
Unfiltered: Girls Vs. Boys At Math: Thu, 10 Sep 2009 00:00:00 +0000 - "Unfiltered" is a recurring series where ScienCentral reporters give their personal thoughts on the stories they produce. This installment is based on the news story "Girls Vs. Boys At Math."
2009 Benjamin Franklin Medal Winner: Stephen Benkovic: Mon, 31 Aug 2009 00:00:00 +0000 - The 2009 Benjamin Franklin Medal in Life Science is presented to Stephen Benkovic for his groundbreaking contributions to our mechanistic understanding of enzymes, and for helping to unravel the complexities of the enzymes involved in DNA replication. This ScienCentral Video Profile explains.
As Goes GM: Mon, 01 Jun 2009 19:23:06 +0000 - I know a woman who is relentlessly, ridiculously optimistic. Everything is always for the best.

Quantum dots are not dots: Tue, 21 Dec 2010 00:00:00 +0100 - Researchers from the Quantum Photonics Group at DTU Fotonik in collaboration with the Niels Bohr Institute,...
New accelerators to ensure cutting edge European research in nuclear physics: Thu, 09 Dec 2010 00:00:00 +0100 - Europe is to get new particle accelerators and the current facilities at CERN, GSI and Ganil must...
CERN observes melted nuclear matter for the first time: Fri, 26 Nov 2010 00:00:00 +0100 - Scientists from the Niels Bohr Institute take part in the ATLAS experiment, where new results show,...
Teachers from across the country flock to the Niels Bohr Institute: Mon, 22 Nov 2010 00:00:00 +0100 - Niels Bohr Institute is hosting a big Theme Day, where high school and secondary school teachers can...
CERN collides heavy ions at record energies: Tue, 09 Nov 2010 00:00:00 +0100 - In the new experiments heavy lead ions are being smashed together with tremendous energy. Already with...
New ultra-clean nanowires have great potential: Mon, 08 Nov 2010 00:00:00 +0100 - New ultra-clean nanowires produced at the Nano-Science Center, University of Copenhagen will have a...
Quantum memory for communication networks of the future: Sun, 07 Nov 2010 00:00:00 +0100 - Researchers from the Niels Bohr Institute have succeeded in storing quantum information using two 'entangled'...
Wild 'teenage'-galaxies booming with star births: Mon, 11 Oct 2010 00:00:00 +0200 - Scientists from the Niels Bohr Institute have been studying distant galaxies, which are among the most...
Nobel Prize to former physicist from Niels Bohr Institute: Tue, 05 Oct 2010 00:00:00 +0200 - The 2010 Nobel laureate in physics has been awarded to Andre Geim and Konstantin Novoselov for their...
Quarks 'swing' to the tones of random numbers: Mon, 27 Sep 2010 00:00:00 +0200 - At the Large Hadron Collider at CERN protons crash into each other at incredibly high energies in order...
Dramatic climate change is unpredictable: Mon, 30 Aug 2010 00:00:00 +0200 - The fear that global temperature can change very quickly and cause dramatic climate changes that may...
Star with planet system and possible super-Earth found: Thu, 26 Aug 2010 00:00:00 +0200 - The first Sun-like star with a planet system consisting of two large planets the size of Saturn, has...
Dark matter is held together by 'attractors': Tue, 10 Aug 2010 00:00:00 +0200 - The universe consists of a large amount of invisible matter – dark matter. We do not know what...
Important step towards quantum communication: Thu, 05 Aug 2010 00:00:00 +0200 - For the first time, researchers from Harvard University and the Niels Bohr Institute have succeeded...
Bedrock of Greenland Ice Sheet reached: Thu, 29 Jul 2010 00:00:00 +0200 - Bedrock has been reached Tuesday July 27 2010 at the deep ice core drilling site NEEM on the Greenland...
Improvement of superconductors within reach: Thu, 08 Jul 2010 00:00:00 +0200 - An international group of physicists from the University of Augsburg in Germany, the University of Florida...
Supernovae mystery solved: Wed, 30 Jun 2010 00:00:00 +0200 - Type Ia supernovae are a relatively homogeneous class of stellar explosions, which researchers use as...
Carbon sequestration: Boon or burden: Sun, 27 Jun 2010 00:00:00 +0200 - The idea to sequester carbon is gaining support as a way to avoid global warming. For example, the European...
The Earth and Moon formed later than previously thought: Mon, 07 Jun 2010 00:00:00 +0200 - The Earth and Moon were created as the result of a giant collision between two planets the size of Mars...
Planck satellite on a mission to the beginning of the Universe: Tue, 18 May 2010 00:00:00 +0200 - ”The mission is going perfectly and we are getting very good data which might explain what happened...
Studies agree on a 1 meter rise in sea levels: Tue, 13 Apr 2010 00:00:00 +0200 - New research from several international research groups, including the Niels Bohr Institute at the University...
Record measurement of extremely small magnetic fields: Mon, 12 Apr 2010 00:00:00 +0200 - Researchers at the research center QUANTOP at the Niels Bohr Institute at the University of Copenhagen...
Launch: New Danish center for space research: Tue, 06 Apr 2010 00:00:00 +0200 - With the aim of strengthening Danish space research, several institutes at the University of Copenhagen...
Big Bang a spectacular success: Wed, 31 Mar 2010 00:00:00 +0200 - The auditorium is packed with visitors, journalists and researchers, who are following the live broadcasts...
Astronomers observe growing black holes: Wed, 17 Mar 2010 00:00:00 +0100 - The most distant quasars found in the early universe, a mere 800 million years after the Big Bang, have...
Rumblings about CERN is empty talk: Mon, 15 Mar 2010 00:00:00 +0100 - ’Hadron Collider to be closed amid fears of a very big bang’ read the headline in a major...
New light shed on old dispute between Einstein and Bohr: Mon, 18 Jan 2010 00:00:00 +0100 - In classical physics there are no uncertainties – the properties of matter on an atomic level...
LIVE - from Big Bang at CERN to Blegdamsvej: Tue, 05 Jan 2010 00:00:00 +0100 - A light installation, a Colliderscope, which transmits signals from the physics experiments at CERN...

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