Bose-Einstein-condensed systems in random potentials

Journal Article · Thu Feb 15 04:00:00 EST 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.75.023619· OSTI ID:20982170

Yukalov, V I ^[1]; Graham, R ^[1]

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1. Fachbereich Physik, Universitaet Duisburg-Essen, 47048 Duisburg (Germany)

The properties of systems with Bose-Einstein condensate in external time-independent random potentials are investigated in the frame of a self-consistent stochastic mean-field approximation. General considerations are presented, which are valid for finite temperatures, arbitrary strengths of the interaction potential, and for arbitrarily strong disorder potentials. The special case of a spatially uncorrelated random field is then treated in more detail. It is shown that the system consists of three components, condensed particles, uncondensed particles, and a glassy density fraction, but that the pure Bose glass phase with only a glassy density does not appear. The theory predicts a first-order phase transition for increasing disorder parameter, where the condensate fraction and the superfluid fraction simultaneously jump to zero. The influence of disorder on the ground-state energy, the stability conditions, the compressibility, the structure factor, and the sound velocity are analyzed. The uniform ideal condensed gas is shown to be always stochastically unstable, in the sense that an infinitesimally weak disorder destroys the Bose-Einstein condensate, returning the system to the normal state; but the uniform Bose-condensed system with finite repulsive interactions becomes stochastically stable and exists in a finite interval of the disorder parameter.

• OSTI ID: 20982170
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 75; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
APPROXIMATIONS
BOSE-EINSTEIN CONDENSATION
COMPRESSIBILITY
CONDENSATES
DENSITY
GROUND STATES
INTERACTIONS
MEAN-FIELD THEORY
PHASE TRANSFORMATIONS
POTENTIALS
RANDOMNESS
SOUND WAVES
STABILITY
STOCHASTIC PROCESSES
STRUCTURE FACTORS
SUPERFLUIDITY
VELOCITY