Impurity Expulsion From a Bose-Einstein CondensateWhen a sizable, hard-sphere-like impurity is placed in a trapped Bose-Einstein condensate, it will create a hole in the condensate wave function. Since it costs more energy to drill a hole at the…Siu A. Chin, Harald A. Forbert·Oct 21, 1998SaveLearn
Quantum Coherence in Fe8 Molecular NanomagnetsWe report observation of coherent quantum oscilations in spin-10 Fe8 molecular clusters. The powder of magnetically oriented Fe8 crystallites was placed inside a resonator, in a dc magnetic field…E. del Barco, N. Vernier, J. M. Hernandez et al.·Oct 20, 1998SaveLearn
Topological Twistons in Crystalline PolyethyleneWe introduce an alternate model to describe twistons in crystalline polyethylene. The model couples torsional and longitudinal degrees of freedom and appears as an extension of a model that describes…D. Bazeia, E. Ventura·Oct 20, 1998SaveLearn
Noise Dressing of Financial Correlation MatricesWe show that results from the theory of random matrices are potentially of great interest to understand the statistical structure of the empirical correlation matrices appearing in the study of price…Laurent Laloux, Pierre Cizeau, Jean-Philippe Bouchaud et al.·Oct 20, 1998SaveLearn
Transport properties of quasiparticles with fractional exclusion statisticsWe consider the ballistic transport of quasiparticles with exclusion statistics through a 1D wire within the Landauer-Buttiker approach. We demonstrate that quasiparticle transport coefficients…I. V. Krive, E. R. Mucciolo·Oct 20, 1998SaveLearn
Finite size errors in quantum many-body simulations of extended systemsFurther developments are introduced in the theory of finite size errors in quantum many-body simulations of extended systems using periodic boundary conditions. We show that our recently introduced…P. R. C. Kent, Randolph Q. Hood, A. J. Williamson et al.·Oct 20, 1998SaveLearn
Molecular crystal approach for pi-conjugated polymers: from PPP Hamiltonian to Holstein model for polaron statesStarting from the π-electron Pariser-Parr-Pople (PPP) Hamiltonian which includes both strong electron-phonon and electron-electron interactions, we propose some strongly correlated wave functions…S. Pleutin, J-L Fave·Oct 19, 1998SaveLearn
Quantum description of the orientational degrees of freedom in a biaxial nematic liquidThe quantum mechanical version of a classical model for studying the orientational degrees of freedom corresponding to a nematic liquid composed of biaxial molecules is presented. The effective…Jorge Alfaro, Oscar Cubero, Luis F. Urrutia·Oct 19, 1998SaveLearn
Dislocations and Bragg glasses in two dimensionsWe discuss the question of the generation of topological defects (dislocations) by quenched disorder in two dimensional periodic systems. In a previous study [Phys. Rev. B 52 1242 (1995)] we…Pierre Le Doussal, Thierry Giamarchi·Oct 19, 1998SaveLearn
Crashes as Critical PointsWe study a rational expectation model of bubbles and crashes. The model has two components : (1) our key assumption is that a crash may be caused by local self-reinforcing imitation between noise…Anders Johansen, Olivier Ledoit, Didier Sornette·Oct 19, 1998SaveLearn
Excitation spectrum of the homogeneous spin liquidWe discuss the excitation spectrum of a disordered, isotropic and translationally invariant spin state in the 2D Heisenberg antiferromagnet. The starting point is the nearest-neighbor RVB state which…R. Eder·Oct 18, 1998SaveLearn
Temperature-dependent density profiles of trapped boson-fermion mixturesWe present a semiclassical three-fluid model for a Bose-condensed mixture of interacting Bose and Fermi gases confined in harmonic traps at finite temperature. The model is used to characterize the…M. Amoruso, A. Minguzzi, S. Stringari et al.·Oct 17, 1998SaveLearn
Bose-Einstein condensation in harmonic double wellsWe discuss Bose-Einstein condensation in harmonic traps where the confinement has undergone a splitting along one direction. We mostly consider the 3D potentials consisting of two cylindrical wells…P. Capuzzi, E. S. Hernandez·Oct 14, 1998SaveLearn
On the Thomas-Fermi approximation for Bose condensates in trapsThomas-Fermi theory for Bose condesates in inhomogeneous traps is revisited. The phase-space distribution function in the Thomas-Fermi limit is f0(R,p) α δ(μ- Hcl) where…P. Schuck, X. Viñas·Oct 14, 1998SaveLearn
Self-Organized Segregation within an Evolving PopulationAn evolving population, in which individual members (`agents') adapt their behaviour according to past experience, is of central importance to many disciplines. Because of their limited knowledge…Neil F. Johnson, Pak Ming Hui, Rob Jonson et al.·Oct 13, 1998SaveLearn
Semiclassical description of Heisenberg models via spin-coherent statesWe use spin-coherent states as a time-dependent variational ansatz for a semiclassical description of a large family of Heisenberg models. In addition to common approaches we also evaluate the square…John Schliemann, Franz G. Mertens·Oct 13, 1998SaveLearn
Thermodynamic properties of spin-1/2 transverse XY chain with Dzyaloshinskii-Moriya interaction: Exact solution for correlated Lorentzian disorderWe extend the consideration of the spin-1/2 transverse XY chain with correlated Lorentzian disorder (Phys. Rev. B 55, 14298 (1997)) for the case of additional Dzyaloshinskii-Moriya interspin…Oleg Derzhko, Johannes Richter·Oct 13, 1998SaveLearn
Effects of Dissipation on Quantum Phase Slippage in Charge Density Wave SystemsWe study the effect of the dissipation on the quantum phase slippage via the creation of ``vortex ring'' in charge density wave (CDW) systems. The dissipation is assumed to come from the…Hiroyuki Miyake, Hiroshi Matsukawa·Oct 12, 1998SaveLearn
Shift Operators for XXX-Heisenberg ChainThe shift operators for XXX-Heisenberg chain are found. They are formed by local Yangian operators and the amplitutes of the eigenfunctions obeying Bethe ansatz for the Hamiltonian. The physical…Jing-Ling Chen, Mo-Lin Ge, Kang Xue·Oct 12, 1998SaveLearn
Vortex Density of States and Absorption in Clean Layered SuperconductorsWe study the spectrum of the states localized in the vortex cores in the mixed state of clean layered superconductors. S-wave coupling is assumed. It is found that in a large region of parameters…A. A. Koulakov, A. I. Larkin·Oct 9, 1998SaveLearn
Quantum degeneracy and interaction effects in spin-polarized Fermi-Bose mixturesVarious features of spin-polarized Fermi gases confined in harmonic traps are discussed, taking into account possible perspectives of experimental measurements. The mechanism of the expansion of the…L. Vichi, M. Inguscio, S. Stringari et al.·Oct 9, 1998SaveLearn
Zero Temperature Phases of the Electron GasThe stability of different phases of the three-dimensional non-relativistic electron gas is analyzed using stochastic methods. With decreasing density, we observe a continuous transition from…G. Ortiz, M. Harris, P. Ballone·Oct 9, 1998SaveLearn
Statistical Analysis of Magnetic Field SpectraWe have calculated and statistically analyzed the magnetic-field spectrum (the ``B-spectrum'') at fixed electron Fermi energy for two quantum dot systems with classically chaotic shape. This…Jian Wang, Hong Guo·Oct 9, 1998SaveLearn
Comment on ``Roughening Transition of Interfaces in Disordered Media''Emig and Nattermann (Phys. Rev. Lett. 81, 1469 (1998)) have recently investigated the competition between lattice pinning and impurity pinning using a Renormalisation Group (RG) approach. For elastic…Anusha Hazareesing, Jean-Philippe Bouchaud·Oct 8, 1998SaveLearn
Coupled exciton model with off-diagonal disorder for optical excitations in extended dendrimersA phenomenological coupled exciton model is proposed in order to characterize optical excitations in extended dendrimers. An onsite exciton state is assigned at each phenyl rings and a nearest…Kikuo Harigaya·Oct 6, 1998SaveLearn