Bose-Einstein condensates in85Rbgases at higher densities

Abstract

The Bose-Einstein condensation in trapped gases of {sup 85}Rb at densities beyond the dilute regime can now be realized taking advantage of Feshbach resonances. The gas density may be characterized by the parameter na{sup 3}, where n=N/V is the number density and a is the scattering length which is tuned using Feshbach resonance. We explore the properties of interacting trapped bosons in the density range 5x10{sup -3}{<=}na{sup 3}{<=}5x10{sup -2} using Monte Carlo methods to compare with experiments. We find that there is a significant depletion of the condensate at T=0 K, for example, 25% at na{sup 3}=10{sup -2}. The condensate is not concentrated at the center of the trap but is spread out over four or five trap lengths. The condensate density distributions and the total density distributions within the trap are very similar and the condensate fraction is 100% at the edges of the trap.