Quantitative test of thermal field theory for Bose-Einstein condensates

TL;DR

This paper numerically tests a second order quantum field theory for Bose-Einstein condensates against experimental data, showing good agreement in energies and decay rates, and explaining anomalous behaviors.

Contribution

It applies a comprehensive second order quantum field theory to BECs, including coupled dynamics and finite size effects, to match experimental observations.

Findings

Good agreement with experimental energies and decay rates

Explains anomalous behavior of the m=0 mode due to perturbation

Includes coupled condensate and thermal cloud dynamics

Abstract

We present numerical results from a full second order quantum field theory of Bose-Einstein condensates applied to the 1997 JILA experiment [D. S. Jin et al., Phys. Rev. Lett. Vol. 78, 764 (1997)]. Good agreement is found for the energies and decay rates for both the lowest-energy m = 2 and m = 0 modes. The anomalous behaviour of the m = 0 mode is due to experimental perturbation of the non-condensate. The theory includes the coupled dynamics of the condensate and thermal cloud, the anomalous pair average and all relevant finite size effects.