Quasiclassical approach to Bose condensation in a finite potential well -: art. no. 045201

We treat the problem of self-consistently interacting bosons in the presence of a finite (but macroscopic) potential well within a quasiclassical approximation for the normal component and the order parameter. We solve the equilibrium problem and show that condensation actually occurs in two steps: one already at low densities with Bose condensation only in the well, and another one corresponding to the usual condensation in bulk. The peak and width of the distribution of trapped particles in the well display a distinct signature of the local condensation. A possible connection to recent experiments with excitons is discussed.