Abstract. We describe recent three-flavor QCD lattice data for the pressure, speed of sound and interaction measure at nonzero temperature and vanishing chemical potential within a virial expansion. For the deconfined phase, we use an effective potential inspired by a phenomenological model which includes non-perturbative effects from dimension-2 gluon condensates that reproduce the free energy of quenched QCD very well. The hadronic phase is parameterized by a generalized resonance-gas model. Furthermore, we extend this approach to finite quark densities introducing an explicit μ_q-dependence of the interaction. We calculate pressure, quark-number density, entropy and energy density and compare to results of lattice calculations. We, additionally, investigate the structure of the phase diagram by calculating the isobaric and isentropic lines as well as the critical endpoint in the (T, μ_q)-plane.

Print publication: Issue 12 (December 2009)
Received 26 June 2009
Published 23 October 2009