Decoherence of Bose-Einstein condensates in traps at finite temperature

TL;DR

This paper investigates the phase diffusion and number fluctuation correlation times in trapped Bose-Einstein condensates at finite temperatures, establishing fundamental limits for atom laser linewidths.

Contribution

It provides a theoretical analysis of phase diffusion and number fluctuations in BECs at high temperatures, linking these phenomena through the fluctuation-dissipation relation.

Findings

Determines the phase diffusion rate at high temperatures.

Predicts the correlation time of number fluctuations.

Relates phase diffusion to number fluctuations via fluctuation-dissipation.

Abstract

The phase diffusion of the order parameter of trapped Bose-Einstein condensates at temperatures large compared to the mean trap frequency is determined, which gives the fundamental limit of the line-width of an atom laser. In addition a prediction of the correlation time of the number fluctuations in the condensate is made and related to the phase diffusion via the fluctuation-dissipation relation.