Coulomb gauge Yang-Mills theory at finite temperatures: glueballs versus quasi-gluons

We consider a variational approach to the finite temperature Yang-Mills theory in the Coulomb gauge. The partition function is computed in the ensemble of glueballs and quasi-gluons which emerge as eigenstates of the Coulomb gauge Hamiltonian. We compute the energy density and pressure and compare with results of lattice computations for both SU(2) and SU(3). The emergence of a phase transition is discussed.