Non-Thomas–Fermi behaviour of a finite-temperature Bose–Einstein condensate in the presence of a thermal cloud

Abstract

We analyse numerically the finite-temperature behaviour of a dilute trapped Bose gas containing a large number of atoms. The generalized Hartree-Fock-Bogoliubov approximation is used to take into account the mutual interactions between the condensate and the thermal cloud. We confront our results with recent experiments and literature and explain in particular the experimentally observed departure from the Thomas-Fermi regime for the condensate radius and the aspect ratio. This clearly illustrates the compression effect of the thermal cloud on the condensate.

Anomalous effects in a trapped Bose-Einstein condensate

“…The equation (2.7) involves an explicitly diverging term (for r = r ′ ) which should be regularized. To this end, one may absorb this diverging expression in a redefinition of the thermal average [7,8,19] or, as performed by [20,21], one may use the pseudopotential method [22] to renormalize the coupling constant. A more rigorous approach is the Λ-potential method first discussed in [9,10].…”