  We discuss the thermodynamics of a non-relativistic gas of bosons with a
local repulsive interaction. In particular, we compute the temperature and
density dependence of pressure, energy and entropy-density, superfluid and
condensate-fraction, correlation length, specific heat, isothermal and
adiabatic compressibility and various sound velocities. The T->0 limit
approaches the quantum phase transition, while the universal critical behavior
of a classical second order phase transition in the O(2) universality class
determines the region around the critical temperature. Our non-perturbative
flow equations based on exact functional renormalization cover all regions in
the phase diagram.
