Variational approach to Yang-Mills theory at finite temperatures
  We study the finite-temperature phase of a gluon ensemble in a variational approximation to QCD in the Coulomb gauge. We derive and numerically solve the underlying Dyson-Schwinger equations up to one-loop order. Assuming the subcritical solution at T=0, we find a sharp transition in the infrared value of the gluon energy at a critical temperature. 
Hugo Reinhardt, Davide R. Campagnari, Adam P. Szczepaniak
hep-th hep-ph