Critical Behaviour of a Homogeneous Bose Gas at Finite Temperature
  A homogeneous non-relativistic Bose gas is investigated at finite temperature using renormalization group methods. The phase transition is shown to be second order and the effective chemical potential and the effective quartic coupling vanish at the critical temperature. We obtain the critical exponent $\nu =0.73$ at leading order in the derivative expansion. 
Jens O. Andersen and Michael Strickland