On the Quasiparticle Description of Lattice QCD Thermodynamics

We propose a novel quasiparticle interpretation of the equation of state of deconfined QCD at finite temperature. Using appropriate thermal masses, we introduce a phenomenological parametrization of the onset of confinement in the vicinity of the predicted phase transition. Lattice results of the energy density, the pressure, and the interaction measure of pure SU(3) gauge theory are excellently reproduced. We find a relationship between the thermal energy density of the Yang-Mills vacuum and the chromomagnetic condensate $〈{\mathbf{B}}^{2}{〉}_{T}.$ Finally, an extension to QCD with dynamical quarks is discussed. Good agreement with lattice data for 2, 2+1, and 3 flavor QCD is obtained. We also present the QCD equation of state for realistic quark masses.