Collective motion and solid-liquid-type transitions in vibrated granular layersFrom pressure and surface dilation measurements, we show that a solid-liquid-type transition occurs at low excitation frequencies in vertically vibrated granular layers. This transition precedes…Nicolas Mujica, Francisco Melo·Aug 17, 1999SaveLearn
Oscillatory screening of the dc electric field in the Si-SiO2 multiple quantum wells probed by second-harmonic generationDC-electric field, being screened in 3D semiconductors, normally decays monotonically in space. Experimental studies of the DC electric field screening in Si-SiO2 multiple quantum wells by…V. V. Savkin, A. A. Fedyanin, A. N. Rubtsov et al.·Aug 17, 1999SaveLearn
Long-Range Excitation of Collective Modes in Mesoscopic Metal ClustersWe develop a semiclassical theory for the long range excitation of plasmon resonances in atomic clusters, based on the doorway hypothesis. The effect of the width of the plasmon resonance is fully…M. S. Hussein, V. Kharchenko, L. F. Canto et al.·Aug 16, 1999SaveLearn
Instability of a Bose-Einstein Condensate with Attractive InteractionWe study the stability of a Bose-Einstein condensate of harmonically trapped atoms with negative scattering length, specifically lithium 7. Our method is to solve the time-dependent nonlinear…Antonios Eleftheriou, Kerson Huang·Aug 16, 1999SaveLearn
Muonium as a hydrogen analogue in silicon and germanium; quantum effects and hyperfine parametersWe report a first-principles theoretical study of hyperfine interactions, zero-point effects and defect energetics of muonium and hydrogen impurities in silicon and germanium. The spin-polarized…A. R. Porter, M. D. Towler, R. J. Needs·Aug 16, 1999SaveLearn
Vortices in a Bose-Einstein CondensateWe have created vortices in two-component Bose-Einstein condensates. The vortex state was created through a coherent process involving the spatial and temporal control of interconversion between the…M. R. Matthews, B. P. Anderson, P. C. Haljan et al.·Aug 14, 1999SaveLearn
Quantum heat transfer through an atomic wireWe studied the phononic heat transfer through an atomic dielectric wire with both infinite and finite lengths by using a model Hamiltonian approach. At low temperature under ballistic transport, the…A. Buldum, S. Ciraci, C. Y. Fong·Aug 13, 1999SaveLearn
Surface Phonons and Other Localized ExcitationsThe diatomic linear chain of masses coupled by harmonic springs is a textboook model for vibrational normal modes (phonons) in crystals. In addition to propagating acoustic and optic branches, this…Philip B. Allen, Seth Aubin, R. B. Doak·Aug 13, 1999SaveLearn
The possibility of a metal insulator transition in antidot arrays induced by an external drivingIt is shown that a family of models associated with the kicked Harper model is relevant for cyclotron resonance experiments in an antidot array. For this purpose a simplified model for electronic…A. Iomin, S. Fishman·Aug 13, 1999SaveLearn
Comparison of perturbative expansions using different phonon bases for two-site Holstein modelThe two-site single-polaron problem is studied within the perturbative expansions using different standard phonon basis obtained through the Lang Firsov (LF), modified LF (MLF) and modified LF…Jayita Chatterjee, A. N. Das·Aug 12, 1999SaveLearn
Yrast line for weakly interacting trapped bosonsWe compute numerically the yrast line for harmonically trapped boson systems with a weak repulsive contact interaction, studying the transition to a vortex state as the angular momentum L increases…George F. Bertsch, Thomas Papenbrock·Aug 12, 1999SaveLearn
Time-dependent tunneling of Bose-Einstein condensatesThe influence of atomic interactions on time-dependent tunneling processes of Bose-Einstein condensates is investigated. In a variety of contexts the relevant condensate dynamics can be described by…O. Zobay, B. M. Garraway·Aug 12, 1999SaveLearn
Nonlinear Modes of a Macroscopic Quantum OscillatorWe consider the Bose-Einstein condensate in a parabolic trap as a macroscopic quantum oscillator and describe, analytically and numerically, its collective modes - a nonlinear generalisation of the…Yuri S. Kivshar, Tristram J. Alexander, Sergey K. Turitsyn·Aug 12, 1999SaveLearn
Mach-Zehnder Bragg interferometer for a Bose-Einstein CondensateWe construct a Mach-Zehnder interferometer using Bose-Einstein condensed rubidium atoms and optical Bragg diffraction. In contrast to interferometers based on normal diffraction, where only a small…Yoshio Torii, Yoichi Suzuki, Mikio Kozuma et al.·Aug 11, 1999SaveLearn
New Tetrahedral Global Minimum for the 98-atom Lennard-Jones ClusterA new atomic cluster structure corresponding to the global minimum of the 98-atom Lennard-Jones cluster has been found using a variant of the basin-hopping global optimization algorithm. The new…Robert Leary, Jonathan Doye·Aug 11, 1999SaveLearn
The Recurrent Variational Approach applied to the Electronic Structure of Conjugated PolymersIn this note, first the Recurrent Variational Approach (RVA) is introduced by using as example a non-trivial spin-model, the spin-1/2 antiferromagnetic two-leg-ladder. Then, a first application of…S. Pleutin, E. Jeckelmann, M. A. Martin-Delgado et al.·Aug 11, 1999SaveLearn
Coherent Ultrafast Optical Dynamics of the Fermi Edge SingularityWe develop a non-equilibrium many-body theory of the coherent femtosecond nonlinear optical response of the Fermi edge singularity. We study the role of the dynamical Fermi sea response in the…N. Primozich, T. V. Shahbazyan, I. E. Perakis et al.·Aug 6, 1999SaveLearn
Proximity Effect in Presence of Quantum FluctuationsThe effect of Coulomb interaction upon superconductive proximity effect in disordered metals is studied, employing newly developed Keldysh functional approach (cond-mat/9907358). We have calculated…M. V. Feigel'man, A. I. Larkin, M. A. Skvortsov·Aug 5, 1999SaveLearn
Transmission of Information and Herd Behavior: an Application to Financial MarketsWe propose a model for stochastic formation of opinion clusters, modelled by an evolving network, and herd behaviour to account for the observed fat-tail distribution in returns of financial-price…Victor M. Eguiluz, Martin G. Zimmermann·Aug 4, 1999SaveLearn
Nonlinear Dynamics of Nuclear-Electronic Spin Processes in FerromagnetsSpin dynamics is considered in ferromagnets consisting of electron and nuclear subsystems interacting with each other through hyperfine forces. In addition, the ferromagnetic sample is coupled with a…V. I. Yukalov, M. G. Cottam, M. R. Singh·Aug 4, 1999SaveLearn
Exact eigenstates and transmission for two interacting electrons on quantum dotsThe eigenstates and the scattering transmission for two interacting electrons are found exactly for I quantum dots, including the hybridization with the states on the leads. The results imply…Amnon Aharony O. Entin-Wohlman, Y. Imry, Y. Levinson·Aug 4, 1999SaveLearn
Semiclassical mechanics of a non-integrable spin clusterWe study detailed classical-quantum correspondence for a cluster system of three spins with single-axis anisotropic exchange coupling. With autoregressive spectral estimation, we find oscillating…P. A. Houle, N. G. Zhang, C. L. Henley·Aug 3, 1999SaveLearn
Kinetic Theory of Collective Modes in Atomic Clouds above the Bose-Einstein Transition TemperatureWe calculate frequencies and damping rates of the lowest collective modes of a dilute Bose gas confined in an anisotropic trapping potential above the Bose-Einstein transition temperature. From the…U. Al Khawaja, C. J. Pethick, H. Smith·Aug 3, 1999SaveLearn
Magnon-Paramagnon Effective Theory of Itinerant FerromagnetsThe present work is devoted to the derivation of an effective magnon-paramagnon theory starting from a microscopic lattice model of ferromagnetic metals. For some values of the microscopic parameters…N. I. Karchev·Aug 2, 1999SaveLearn
The Phase Diagrams of F=2 Spinor Bose CondensatesWe show that there are three possible phases for a spin-2 spinor Bose condensate, one more compared to the spin-1 case. The order parameters of these phases are the spontaneous magnetization and the…C. V. Ciobanu, S. K. Yip, T. L. Ho·Aug 2, 1999SaveLearn