Phase fluctuations in atomic Bose gases

Abstract

We improve the Popov theory for partially Bose-Einstein condensed atomic gases by treating the phase fluctuations exactly. As a result, the theory becomes valid in arbitrary dimensions and is able to describe the low-temprature crossover between three, two and one-dimensional Bose gases, which is currently beeing explored experimentally. When applied to a degenerate two-dimensional atomic hydrogen gas, we find reasonable agreement with recent experimental data for the reduction of the tree-body recombination rate.