Finite temperature excitations of Bose gases in anisotropic traps
  The mode frequencies of a weakly interacting Bose gas in a magnetic trap are studied as a function of the anisotropy of the trap. As in earlier works the generalized Hartree-Fock-Bogoliubov equations within the Popov approximation (HFB-Popov) are used for our calculations. The new feature of our work is the combined use of a mode expansion in a finite basis and a semiclassical approximation of the highly excited states. The results are applied to check the accuracy of the recently suggested equivalent zero-temperature condensate (EZC) approximation which involves a much simpler model. 
J. Reidl (1), A. Csord\'as (2), R. Graham (1), P.Sz\'epfalusy(3) ((1)   Fachbereich Physik, Universit\"at Gesamthochschule E...