Mean-field theory for excitations of trapped Bose condensates at finite temperatures

被引:20
作者
Rusch, M [1 ]
Burnett, K [1 ]
机构
[1] Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England
关键词
D O I
10.1103/PhysRevA.59.3851
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
We describe a method for studying the dynamics of a condensate in a weakly interacting, dilute Bose gas which is based on a finite-temperature extension of the Gross-Pitaevskii equation. We present a general finite-temperature linear response formalism for nonuniform systems and give explicit results for homogeneous ones, where we can link our treatment to well-known results. This treatment leads to a consistent V-2 calculation of the excitations for a weakly interacting Bose gas, including Landau and Beliaev damping as well as collisional lifetimes. We do not make use of the Popov approximation, but include pair and triplet anomalous averages to second order in the interaction potential and thus obtain a gapless theory for the excitations of a weakly interacting homogeneous gas. We also show how the formalism can be used to obtain self-consistent theories. We explicitly derive gapless equations for a weakly coupled finite-temperature condensate with a static thermal component and give a clear criterion of their validity in trapped systems. [S1050-2947(99)04005-6].
引用
收藏
页码:3851 / 3861
页数:11
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