Publication Date

2002

Journal or Book Title

JOURNAL OF LOW TEMPERATURE PHYSICS

Abstract

We study the Hartree–Fock–Bogoliubov mean-field theory as applied to a two-dimensional finite trapped Bose gas at low temperatures and find that, in the Hartree–Fock approximation, the system can be described either with or without the presence of a condensate; this is true in the thermodynamic limit as well. Of the two solutions, the one that includes a condensate has a lower free energy at all temperatures. However, the Hartree–Fock scheme neglects the presence of phonons within the system, and when we allow for the possibility of phonons we are unable to find condensed solutions; the uncondensed solutions, on the other hand, are valid also in the latter, more general scheme. Our results confirm that low-energy phonons destabilize the two-dimensional condensate.

Comments

This is the pre-published version which is collected from arXiv. The published version is at http://www.springerlink.com/content/t584ll5162j44172/

Pages

233-249

Volume

128

Issue

5-6

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