Low temperature theory for Bose-Einstein condensates

L. E. Reichl, Minh-Binh Tran

Abstract Bose–Einstein condensates (BECs) are starting to play a role in quantum information processing, and there is a need to better understand the dynamical processes at play in the condensates. In this paper, we review recent work on a kinetic model for ultra-low temperature dilute Bose–Einstein condensates that gives correct behavior for first and second sound speeds at very low temperature, and gives explicit expressions and values for decay processes. The predictions of the theory are in agreement with experiment. The method explicitly computes the hydrodynamic modes of the condensate using a method that has also been used to describe decay processes in noble gas mixtures, and thereby opens the way for future analysis of decay processes in BEC mixtures.

Kunal K. Das

Adelchi Fabrocini

正人 大矢

We present the theory of low-energy collective excitations of a trapped Bose-Einstein condensate which includes the dynamics of thermal quasiparticles. A general expression of the mode frequency and the damping rate is obtained for trapped Bose gases at finite temperatures.

David A. W. Hutchinson

Tai Tsun Wu

The theory of Bose-Einstein condensation for a dilute gas with short-range pairwise repulsive interaction is developed when an external potential is present.At low temperatures when the Bose-Einstein condensation is nearly complete, a partial differential equation is obtained for the condensate wave function and an integro-differential equation for the pair excitation.