Dimensional and Temperature Crossover in Trapped Bose Gases

TL;DR

This paper explores how the phase coherence in trapped Bose gases varies with trap geometry, temperature, and interactions, highlighting the crossover phenomena and their experimental implications.

Contribution

It provides a detailed phase diagram considering quantum and thermal fluctuations, including both phase and density fluctuations, which advances understanding of coherence in Bose gases.

Findings

Identification of dimensional and temperature crossover points

Explicit phase diagram including fluctuation effects

Discussion on experimental observability of crossovers

Abstract

We investigate the long-range phase coherence of homogeneous and trapped Bose gases as a function of the geometry of the trap, the temperature, and the mean-field interactions in the weakly interacting limit. We explicitly take into account the (quasi)condensate depletion due to quantum and thermal fluctuations, i.e., we include the effects of both phase and density fluctuations. In particular, we determine the phase diagram of the gas by calculating the off-diagonal one-particle density matrix and discuss the various crossovers that occur in this phase diagram and the feasibility of their experimental observation in trapped Bose gases.