Microscopic Evolution of a Weakly Interacting Homogeneous Bose Gas

Abstract

We provide a detailed description of the nonequilibrium time evolution of an interacting homogeneous Bose-Einstein condensate. We use a nonperturbative in-medium quantum field theory approach as a microscopic model for the Bose gas. The real-time dynamics of the condensate is encoded in a set of self-consistent equations which corresponds to an infinite sum of ladder Feynman diagrams. The crucial role played by the interaction between fluctuations for the instability generation is thoroughly described.

Comments: 7 pages, 1 figure (uses epsfig). To appear in Laser Physics (2001), Special Issue on Bose-Einstein Condensation of Trapped Atoms. A few misprints and errors have been corrected