First principles simulations of liquid Fe-S under Earth's core conditionsFirst principles electronic structure calculations, based upon density functional theory within the generalized gradient approximation and ultra-soft Vanderbilt pseudopotentials, have been used to…Dario Alfe`, Michael J. Gillan·Apr 3, 1998SaveLearn
Soliton mediated protein foldingA novel approach to protein folding dynamics is presented. We suggest that folding of protein may be mediated via interaction with solitons which propagate along the molecular chain. A simple toy…S. Caspi, E. Ben-Jacob·Apr 3, 1998SaveLearn
Magnetic hysteresis in Ising-like dipole-dipole modelUsing zero temperature Monte Carlo simulations we have studied the magnetic hysteresis in a three-dimensional Ising model with nearest neighbor exchange and dipolar interaction. The average…Gyorgy Szabo, Gyorgy Kadar·Apr 3, 1998SaveLearn
Feshbach Resonance and Hybrid Atomic/Molecular BEC-SystemsThe interactions responsible for Feshbach resonances in binary atom collisions produce a condensate of molecules in the atomic BEC-system. We discuss the `ground state' of the condensate system…Paolo Tommasini, Eddy Timmermans, Mahir Hussein et al.·Apr 2, 1998SaveLearn
The Decay Properties of the Finite Temperature Density Matrix in MetalsUsing ordinary Fourier analysis, the asymptotic decay behavior of the density matrix F(r,r') is derived for the case of a metal at a finite electronic temperature. An oscillatory behavior which…S. Goedecker·Apr 2, 1998SaveLearn
Quantum Monte Carlo calculations of the one-body density matrix and excitation energies of siliconQuantum Monte Carlo (QMC) techniques are used to calculate the one-body density matrix and excitation energies for the valence electrons of bulk silicon. The one-body density matrix and energies are…P. R. C. Kent, Randolph Q. Hood, M. D. Towler et al.·Apr 2, 1998SaveLearn
Calculating photonic Green's functions using a non-orthogonal finite difference time domain methodIn this paper we shall propose a simple scheme for calculating Green's functions for photons propagating in complex structured dielectrics or other photonic systems. The method is based on an…A. J. Ward, J. B. Pendry·Apr 1, 1998SaveLearn
Generalizing the O(N)-field theory to N-colored manifolds of arbitrary internal dimension DWe introduce a geometric generalization of the O(N)-field theory that describes N-colored membranes with arbitrary dimension D. As the O(N)-model reduces in the limit N->0 to self-avoiding polymers,…Kay Joerg Wiese, Mehran Kardar·Mar 31, 1998SaveLearn
Spinon statistics in integrable spin-S Heisenberg chainsThe spectrum of the integrable spin-S Heisenberg chains is completely characterized in terms of spin-1/2 spinons. In the continuum limit they form a quasi-particle basis to the higher level SU(2)…Holger Frahm, Martin Stahlsmeier·Mar 31, 1998SaveLearn
Towards a quantum-chemical description of crystalline insulators: A Wannier-function-based Hartree-Fock study of Li2O and Na2OA recently proposed approach for performing electronic-structure calculations on crystalline insulators in terms of localized orthogonal orbitals is applied to the oxides of lithium and sodium, Li2O…Alok Shukla, Michael Dolg, Peter Fulde et al.·Mar 31, 1998SaveLearn
A Hartree-Fock ab initio band-structure calculation employing Wannier-type orbitalsAn ab initio Wannier-function-based approach to electronic ground-state calculations for crystalline solids is outlined. In the framework of the linear combination of atomic orbitals method the…Martin Albrecht, Alok Shukla, Michael Dolg et al.·Mar 31, 1998SaveLearn
The spin-Peierls instability in spin 1/2 XY chain in the non adiabatic limitThe spin-Peierls instability in spin 1/2 XY chain coupled to dispersionless phonons of frequency ω has been studied in the nonadiabatic limit. We have chosen the Lang-Firsov variational wave…Shreekantha Sil·Mar 31, 1998SaveLearn
Quantum mechanics of chaotic billiardsWe study the quantum behaviour of chaotic billiards which exhibit classically diffusive behaviour. In particular we consider the stadium billiard and discuss how the interplay between quantum…Giulio Casati, Tomaz Prosen·Mar 30, 1998SaveLearn
Single Particle and Fermi Liquid Properties of He-3/--He-4 Mixtures: A Microscopic AnalysisWe calculate microscopically the properties of the dilute He-3 component in a He-3/--He-4 mixture. These depend on both, the dominant interaction between the impurity atom and the background, and the…E. Krotscheck, J. Paaso, M. Saarela et al.·Mar 29, 1998SaveLearn
On the exciton binding energy in a quantum wellWe consider a model describing the one-dimensional confinement of an exciton in a symmetrical, rectangular quantum-well structure and derive upper and lower bounds for the binding energy Eb of the…B. Gerlach, J. Wuesthoff, M. O. Dzero et al.·Mar 28, 1998SaveLearn
Global Optimization by Basin-Hopping and the Lowest Energy Structures of Lennard-Jones Clusters Containing up to 110 AtomsWe describe a global optimization technique using `basin-hopping' in which the potential energy surface is transformed into a collection of interpenetrating staircases. This method has been…David Wales, Jonathan Doye·Mar 27, 1998SaveLearn
Berry-Robnik level statistics in a smooth billiard systemBerry-Robnik level spacing distribution is demonstrated clearly in a generic quantized plane billiard for the first time. However, this ultimate semi-classical distribution is found to be valid only…Tomaz Prosen·Mar 27, 1998SaveLearn
Quantum localization and cantori in chaotic billiardsWe study the quantum behaviour of the stadium billiard. We discuss how the interplay between quantum localization and the rich structure of the classical phase space influences the quantum dynamics.…Giulio Casati, Tomaz Prosen·Mar 27, 1998SaveLearn
Hole-Pairs in a Spin Liquid: Influence of Electrostatic Hole-Hole RepulsionThe stability of hole bound states in the t-J model including short-range Coulomb interactions is analyzed using computational techniques on ladders with up to 2 × 30 sites. For a…C. Gazza, G. Martins, J. Riera et al.·Mar 26, 1998SaveLearn
Dynamical response of a Bose-Einstein condensate to a discontinuous change in internal stateA two-photon transition is used to convert an arbitrary fraction of the 87Rb atoms in a |F=1,mf=-1> condensate to the |F=2,mf=1> state. Transferring the entire population imposes a discontinuous…M. R. Matthews, D. S. Hall, D. S. Jin et al.·Mar 25, 1998SaveLearn
A Mesoscopic Approach to the ``Negative'' Viscosity Effect in FerrofluidsWe present a mesoscopic approach to analyze the dynamics of a single magnetic dipole under the influence of an oscillating magnetic field, based on the formulation of a Fokker-Planck equation. The…A. Perez Madrid, T. Alarcon, J. M. G. Vilar et al.·Mar 25, 1998SaveLearn
Structure and stability of bosonic clouds: alkali atoms with negative scattering lengthWe investigate the form and stability of a cloud of atoms confined in a harmonic trap when the scattering length is negative. We find that, besides the known low density metastable solution, a new…Alberto Parola, Luca Salasnich, Luciano Reatto·Mar 25, 1998SaveLearn
Effect of nonlinearity on the dynamics of a particle in dc field-induced systemsDynamics of a particle in a perfect chain with one nonlinear impurity and in a perfect nonlinear chain under the action of dc field is studied numerically. The nonlinearity appears due to the…P. K. Datta, A. M. Jayannavar·Mar 25, 1998SaveLearn
Solids with weak and strong electron correlationsA number of methods are discussed which may serve for a treatment of electron correlations in solids. When the electron correlations are relatively weak like in semiconductors or a number of ionic…Prof. Dr. Peter Fulde·Mar 25, 1998SaveLearn
Bose-Einstein condensate in a double-well potential as an open quantum systemWe study the dynamics of a Bose-Einstein condensate in a double-well potential in the two-mode approximation. The dissipation of energy from the condensate is described by the coupling to a thermal…Janne Ruostekoski, Dan F. Walls·Mar 25, 1998SaveLearn