Quantitative test of thermal field theory for Bose-Einstein condensates

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.