Equation of state of a quark-meson mixture in the improved-PNJL model at finite chemical potential

Abstract

We study the equation of state of QCD using an improved version of the three-flavor Polyakov-Nambu-Jona-Lasinio model beyond the mean-field approximation. It incorporates the effects of unquenched quarks into the Polyakov-loop effective potential, as well as mesonic contributions to the grand-canonical potential. We study in full detail the calculation of the thermodynamical potential in this approach and compare the resulting pressure and entropy density with the most-recent lattice-QCD calculations at zero baryochemical potential. Finally, we present some exploratory results at finite chemical potential which include the phase diagram of the model, the quark and meson masses, and finally, the thermodynamical pressure.

Comments: 44 pages, 23 figures. Small improvements and more explanations added. Reference list updated. Comparison with recent lattice-QCD results incorporated. Version accepted by the Physical Review C journal