Quasiparticle Interactions and the Bose-Einstein Phase Transition

We look at a strongly interacting Bose gas in an attempt to understand the effects upon the physics of the phase transition of the interactions between the higher momentum excitations. At densities an order of magnitude below liquid helium, we find that these interactions are affecting the phase transition in a manner reminiscent of the effects of roton-roton interactions upon the lambda transition. We find singularities in the specific heat and infinite slope at the transition temperature for the superfluid density.