Rotational quantum friction in superfluids: Radiation from object rotating in superfluid vacuumWe discuss the friction experienced by the body rotating in superfluid liquid at T=0. The effect is analogous to the amplification of electromagnetic radiation and spontaneous emission by the body or…A. Calogeracos, G. E. Volovik·Jan 18, 1999SaveLearn
Component separation in harmonically trapped boson-fermion mixturesWe present a numerical study of mixed boson-fermion systems at zero temperature in isotropic and anisotropic harmonic traps. We investigate the phenomenon of component separation as function of the…Nicolai Nygaard, Klaus Moelmer·Jan 18, 1999SaveLearn
Electron-lattice relaxation, and soliton structures and their interactions in polyenesDensity matrix renormalisation group calculations of a suitably parametrised model of long polyenes (polyacetylene oligomers), which incorporates both long range Coulomb interactions and adiabatic…Robert J. Bursill, William Barford·Jan 14, 1999SaveLearn
Collectivity in the Brain Sensory ResponseA question of cooperative effects in auditory brain processing on various space- and time-scales is addressed. The experimental part of our study is based on Multichannel Magnetoencephalography…S. Drozdz, J. Kwapien, A. A. Ioannides et al.·Jan 14, 1999SaveLearn
Classical diffusion of N interacting particles in one dimension: General results and asymptotic lawsI consider the coupled one-dimensional diffusion of a cluster of N classical particles with contact repulsion. General expressions are given for the probability distributions, allowing to obtain the…Claude Aslangul·Jan 14, 1999SaveLearn
The Theory of Superfluidity of 4HeliumI present here a microscopic theory for the superfluidity of 4He (He II) derived from experiments, and answer its essential questions. With a "momenton" model, the superfluid is shown to…J. X. Zheng-Johansson·Jan 14, 1999SaveLearn
Ripplonic Polaron in the Quasi-One-Dimensional Electron System over Liquid HeliumWe study the energetics and transport properties of polarons in the quasi-one dimensional electron system over the liquid helium surface. The localization lengths and the energy of the ground and…Sviatoslav S. Sokolov, Nelson Studart·Jan 13, 1999SaveLearn
A Brief History of Our Understanding of BEC: From Bose to BeliaevWe review how our current ideas about BEC developed in the early period 1925-1965, which had the specific goal of understanding superfluid 4He. This history is presented by commenting on the key…Allan Griffin·Jan 13, 1999SaveLearn
Bosons in a Toroidal Trap: Ground State and VorticesWe study the Bose-Einstein condensate (BEC) in a 3-D toroidal Mexican hat trap. By changing the parameters of the potential, or the number of bosons, it is possible to modify strongly the density…L. Salasnich, A. Parola, L. Reatto·Jan 13, 1999SaveLearn
Possibility of direct Mott insulator-to-superfluid transitions in weakly disordered boson systemsWe study the zero-temperature phase transitions of a two-dimensional disordered boson Hubbard model at incommensurate boson densities. Via matrix diagonalization and quantum Monte Carlo simulations,…Sung Yong Park, Ji-Woo Lee, Min-Chul Cha et al.·Jan 13, 1999SaveLearn
A theoretical investigation of the low lying electronic structure of poly(p-phenylene vinylene)The two-state molecular orbital model of the one-dimensional phenyl-based semiconductors is applied to poly(p-phenylene vinylene). The energies of the low-lying excited states are calculated using…Mikhail Yu. Lavrentiev, William Barford, Simon J. Martin et al.·Jan 13, 1999SaveLearn
Bragg spectroscopy of a Bose-Einstein condensateProperties of a Bose-Einstein condensate were studied by stimulated, two-photon Bragg scattering. The high momentum and energy resolution of this method allowed a spectroscopic measurement of the…J. Stenger, S. Inouye, A. P. Chikkatur et al.·Jan 12, 1999SaveLearn
Statistical properties of fractures in damaged materialsWe introduce a model for the dynamics of mud cracking in the limit of of extremely thin layers. In this model the growth of fracture proceeds by selecting the part of the material with the smallest…A. Gabrielli, R. Cafiero, G. Caldarelli·Jan 12, 1999SaveLearn
Elementary mechanisms governing the dynamics of silicaA full understanding of glasses requires an accurate atomistic picture of the complex activated processes that constitute the low-temperature dynamics of these materials. To this end, we generate…Normand Mousseau, G. T. Barkema, Simon W. de Leeuw·Jan 12, 1999SaveLearn
A unified description of static and dynamic properties of Fermi liquidsIn Landau's phenomenological Fermi-liquid theory (FLT), most physical quantities are derived from the knowledge of the energy variation δE[δn] corresponding to a change δn of the…N. Dupuis·Jan 12, 1999SaveLearn
Berry Phase and the Symmetry of the Vibronic Ground State in Dynamical Jahn-Teller SystemsDue to the frequent presence of a Berry phase, in most cases of dynamical Jahn-Teller systems the symmetry of the ground state is the same as that of the electronic state. However, the H x h…Nicola Manini, Paolo De Los Rios·Jan 12, 1999SaveLearn
Phenomenology of the Term Structure of Interest Rates with Pade ApproximantsThe classical approach in finance attempts to model the term structure of interest rates using specified stochastic processes and the no arbitrage argument. Up to now, no universally accepted theory…Jean Nuyts, Isabelle Platten·Jan 12, 1999SaveLearn
Magnetic-Field-Induced Exciton Tunneling in Shallow Quantum WellsWe study the effect of the magnetic field orientation on the electroabsorption spectra of excitons confined in extremely shallow quantum wells. When the applied electric field is parallel to the…A. Getter, I. E. Perakis·Jan 12, 1999SaveLearn
Algebraic properties of an integrable t-J model with impuritiesWe investigate the algebraic structure of a recently proposed integrable t-J model with impurities. Three forms of the Bethe ansatz equations are presented corresponding to the three choices for…Angela Foerster, Jon Links, Arlei Prestes Tonel·Jan 11, 1999SaveLearn
Tunneling problems by quantum Monte CarloWe develop a new numerical scheme which allows precise solution of coherent tunneling problems, i.e., problems with exponentially small transition amplitudes between quasidegenerate states. We…Nikolai Prokof'ev, Boris Svistunov, Igor Tupitsyn·Jan 11, 1999SaveLearn
Density matrix renormalization group for disordered bosons in one dimensionWe calculate the zero-temperature phase diagram of the disordered Bose-Hubbard model in one dimension using the density matrix renormalization group. For integer filling the Mott insulator is always…S. Rapsch, U. Schollwoeck, W. Zwerger·Jan 11, 1999SaveLearn
A Unified Algebraic Approach to Few and Many-Body Hamiltonians having Linear SpectraWe develop an algebraic approach for finding the eigenfunctions of a large class of few and many-body Hamiltonians, in one and higher dimensions, having linear spectra. The method presented enables…N. Gurappa, Prasanta K. Panigrahi, T. Soloman Raju·Jan 9, 1999SaveLearn
Theory of sound attenuation in glasses: The role of thermal vibrationsSound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound…Jaroslav Fabian, Philip B. Allen·Jan 8, 1999SaveLearn
Long range Neel order in the triangular Heisenberg modelWe have studied the Heisenberg model on the triangular lattice using several Quantum Monte Carlo (QMC) techniques (up to 144 sites), and exact diagonalization (ED) (up to 36 sites). By studying the…L. Capriotti, A. Trumper, S. Sorella·Jan 8, 1999SaveLearn
Solidity of viscous liquids II: Anisotropic flow eventsRecent findings on the displacements in the surroundings of isotropic flow events in viscous liquids [Phys. Rev. E, to appear Feb. 1999] are generalized to the anisotropic case. Also, it is shown…Jeppe. C. Dyre·Jan 8, 1999SaveLearn