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Condensed Matter papers — page 204

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Cluster maximization, non-locality, and random tilings
Jeong and Steinhardt (JS) implement local rules by selecting the sub-ensemble of tilings which have the maximum occurrences of a chosen pattern (``cluster'') C It is unknown how to prove that…
C. L. HenleyJul 30, 1997
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Superfluidity in sympathetic cooling with atomic Bose condensates
The dynamical structure of an atomic Bose-Einstein condensate limits the efficiency of the condensate in cooling slow impurity atoms. To illustrate the point, we show that an impurity atom moving in…
E. Timmermans, R. CoteJul 30, 1997
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Quasi-Homogeneous Dynamical Structure Factor for Atomic-Trap Bose Condensates
The essence of the Thomas-Fermi model is the assumption that the local behavior of a many-body system can be approximated by that of a homogeneous system. In this paper, we present the natural…
Eddy Timmermans, Paolo TommasiniJul 30, 1997
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Resonant Light Scattering to Measure BEC-Pairing
We present a single-scattering formalism for incoherent resonant light scattering by dilute quantum gas systems such as the atomic-trap Bose-Einstein condensates. We show that resonant scattering…
Eddy Timmermans, Paolo TommasiniJul 30, 1997
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Gaussian Time-Dependent Variational Principle for Bosons Contact Interaction in one dimension
We investigate the Dirac time-dependent variational method using a Gaussian trial functional for an infinite one dimensional system of Bosons interacting through a repulsive contact interaction. The…
Arthur K. Kerman, Paolo TommasiniJul 30, 1997
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Gaussian Time-Dependent Variational Principle for Bosons I - Uniform Case
We investigate the Dirac time-dependent variational method for a system of non-ideal Bosons interacting through an arbitrary two body potential. The method produces a set of non-linear time dependent…
Arthur K. Kerman, Paolo TommasiniJul 30, 1997
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Localization in simple multiparticle catalytic absorption model
We consider the phase transition in the system of n simultaneously developing random walks on the halfline x>=0. All walks are independent on each others in all points except the origin x=0, where…
Sergei NechaevJul 30, 1997
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Two-dimensional oriented self-avoiding walks with parallel contacts
Two closely related models of oriented self-avoiding walks (OSAWs) on a square lattice are studied. We use the pruned-enriched Rosenbluth method to determine numerically the phase diagram. Both…
G. T. Barkema, U. Bastolla, P. GrassbergerJul 30, 1997
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Disordering effects of color in nonequilibrium phase transitions induced by multiplicative noise
The model introduced by Van den Broeck, Parrondo and Toral [Phys. Rev. Lett.73, 3395 (1994)] -- leading to a second-order-like noise-induced nonequilibrium phase transition which shows reentrance as…
S. Mangioni, R. Deza, H. S. Wio et al.Jul 30, 1997
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Self-consistent calculation of particle-hole diagrams on the Matsubara frequency: FLEX approximation
We implement the numerical method of summing Green function diagrams on the Matsubara frequency axis for the fluctuation exchange (FLEX) approximation. Our method has previously been applied to the…
J. J. Rodríguez-Núñez, S. SchafrothJul 29, 1997
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Excitation energies from density functional perturbation theory
We consider two perturbative schemes to calculate excitation energies, each employing the Kohn-Sham Hamiltonian as the unperturbed system. Using accurate exchange-correlation potentials generated…
Claudia Filippi, C. J. Umrigar, X. GonzeJul 29, 1997
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Nonequilibrium Steady States of Driven Periodic Media
We study a periodic medium driven over a random or periodic substrate. Our work is based on nonequilibrium continuum hydrodynamic equations of motion, which we derive microscopically. We argue that…
Leon Balents, M. Cristina Marchetti, Leo RadzihovskyJul 29, 1997
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Random Matrix Theories in Quantum Physics: Common Concepts
We review the development of random-matrix theory (RMT) during the last decade. We emphasize both the theoretical aspects, and the application of the theory to a number of fields. These comprise…
Thomas Guhr, Axel Mueller-Groeling, Hans A. WeidenmuellerJul 29, 1997
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Spin Wave Instability of Itinerant Ferromagnet
We show variationally that instability of the ferromagnetic state in the Hubbard model is largely controlled by softening of a long-wavelength spin-wave excitation, except in the over-doped…
Takuya OkabeJul 29, 1997
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Nucleation in two dimensional Ising system: Classical theory and computer simulation
We have studied the nucleation in the two dimensional Ising model by Monte Carlo simulation. The nucleation time has been studied as a function of the magnetic field for various system sizes. The…
Muktish AcharyyaJul 29, 1997
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Geometry of N-particle clusters in two-dimensions: Some exact results
We report on a study of a finite system of classical confined particles in two-dimensions in the presence of a uniform magnetic field and interacting via a two-body repulsive potential. We develop a…
G. Date, M. V. N. MurthyJul 29, 1997
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Low-temperature regimes and finite-size scaling in a quantum spherical model
A d--dimensional quantum model in the spherical approximation confined to a general geometry of the form Ld-d ×∞d× Lτz (L--linear space size and…
H. Chamati, D. M. Danchev, E. S. Pisanova et al.Jul 28, 1997
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Pade approximants for the ground-state energy of closed-shell quantum dots
Analytic approximations to the ground-state energy of closed-shell quantum dots (number of electrons from 2 to 210) are presented in the form of two-point Pade approximants. These Pade approximants…
A. Gonzalez, B. Partoens, F. M. PeetersJul 24, 1997
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NMR Spin-Spin Relaxation as Kinetics in Spin Phase Space
A new approach is presented that treats NMR spin-spin relaxation as kinetics in spin phase space. The approach is applied to free induction decay (FID) in solids containing equivalent nuclear spins…
Boris V. FineJul 23, 1997
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Electrically tunable GHz oscillations in doped GaAs-AlAs superlattices
Tunable oscillatory modes of electric-field domains in doped semiconductor superlattices are reported. The experimental investigations demonstrate the realization of tunable, GHz frequencies in…
J. Kastrup, R. Hey, K. H. Ploog et al.Jul 23, 1997
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Current-voltage characteristic and stability in resonant-tunneling n-doped semiconductor superlattices
We review the occurrence of electric-field domains in doped superlattices within a discrete drift model. A complete analysis of the construction and stability of stationary field profiles having two…
A. Wacker, M. Moscoso, M. Kindelan et al.Jul 23, 1997
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Short time dynamics of a two dimensional majority vote model
Short time Monte Carlo methods are used to study the nonequilibrium ferromagnetic phase transition in a majority vote model in two dimensions. The existance of an initial critical slip regime is…
J. F. F. Mendes, M. A. SantosJul 23, 1997
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Resonance transmission through a single atom
When a single atom is sandwiched in between two electrodes, an atomic tunneling device may be realized depending on the distance between the atom and the electrodes. We have performed…
José-Luis Mozos, C. C. Wan, Gianni Taraschi et al.Jul 23, 1997
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Breit-Wigner width and participation ratio in finite interacting Fermi systems
For many-body Fermi systems we determine the dependence of the Breit-Wigner width and inverse participation ratio (IPR) on interaction strength U > Uc and energy excitation dE > dEch when a…
Bertrand Georgeot, Dima L. ShepelyanskyJul 22, 1997
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Distribution of Eigenvalues in Non-Hermitian Anderson Model
We develop a theory which describes the behaviour of eigenvalues of a class of one-dimensional random non-Hermitian operators introduced recently by Hatano and Nelson. Under general assumptions on…
Ilya Ya. Goldsheid, Boris A. KhoruzhenkoJul 22, 1997
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