Critical temperature of a trapped, weakly interacting Bose gas
Résumé
We report on measurements of the critical temperature of aharmonically trapped, weakly interacting Bose gas as a function ofatom number. We exclude ideal-gas behavior by more than twostandard deviations, and find agreement with mean-field theory. Wefind no evidence for the presence of critical fluctuations, aswould exist in a uniform gas. In the course of this measurement,the onset of hydrodynamic expansion in the thermal component hasbeen observed. Our thermometry method takes this feature intoaccount.