Transition Temperature of Dilute, Weakly Repulsive Bose Gas

Inter-particle correlations in the weakly repulsive dilute Bose gas have been studied for more than half a century. It is therefore quite remarkable that the dependence of the Bose-Einstein condensation temperature (Tc) on the interaction strength has continued to generate controversy until this time. In this paper we present an analysis of the longstanding Tc problem starting from a quasiparticle picture of the system in the un-condensed (high-temperature) side. The model is described by the Hamiltonian ˆ H = X k ǫk ˆ † ˆ bk + 1 2V X p,q,k