Emergence of interaction effects in Bose-Einstein condensation

We present a quantitative evaluation of the predictions of mean-field theory for describing a Bose-Einstein condensate in a magnetic trap by comparing directly with experimental observations. We study the release energy from ballistic expansion and the cloud density profile as a function of mean-field effects. Significant departure of the cloud shape from both the noninteracting limit and the strongly repulsive limit is observed for our parameters, consistent with theoretical prediction