Second-Order Shift of the Bose-Einstein Condensation Temperature
of a Weakly Interacting Bose Gas

Boris Kastening

Institute for Theoretical Physics, FU Berlin, Arnimallee 14, 12169 Berlin, Germany

We present the computation of the shift of the Bose-Einstein condensation temperature of a weakly interacting Bose gas through second order in the scattering length, both for the homogenous gas and the case of a wide trap. Resummed perturbation theory through seven loops is used to deal with the infrared divergences of this non-perturbative problem. We compare our results with those of Monte-Carlo simulations.