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arXiv · 1309.0060

Comparative studies of many-body corrections to an interacting Bose condensate

Shohei Watabe·Yoji Ohashi
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Abstract

We compare many-body theories describing fluctuation corrections to the mean-field theory in a weakly interacting Bose-condensed gas. Using a generalized random-phase approximation, we include both density fluctuations and fluctuations in the particle-particle scattering channel in a consistent manner. We also separately examine effects of the fluctuations within the framework of the random-phase approximation. Effects of fluctuations in the particle-particle scattering channel are also separately examined by using the many-body T-matrix approximation. We assess these approximations with respect to the transition temperature, the order of phase transition, as well as the so-called Nepomnyashchii-Nepomnyashchii identity, which states the vanishing off-diagonal self-energy in the low-energy and low-momentum limit. Since the construction of a consistent theory for interacting bosons which satisfies various required conditions is a long standing problem in cold atom physics, our results would be useful for this important challenge.

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Shohei Watabe, Yoji Ohashi. 2013-11-18. Comparative studies of many-body corrections to an interacting Bose condensate. https://doi.org/10.1103/physreva.88.053633

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