Including the Fermion Vacuum Fluctuations in the $(2+1)$ flavor Polyakov Quark Meson Model

TL;DR

This paper enhances the $(2+1)$ flavor Polyakov Quark Meson Model by incorporating fermion vacuum fluctuations, leading to improved thermodynamic predictions and insights into the QCD phase diagram.

Contribution

It introduces the inclusion of fermion vacuum fluctuations into the model, which refines thermodynamic predictions and phase transition characteristics.

Findings

Smoother thermodynamic behavior across the phase transition.

Better agreement with lattice QCD data.

Vacuum fluctuations influence the existence and position of the critical end point.

Abstract

We consider the $(2+1)$ flavor Polyakov Quark Meson Model and study the effect of including fermion vacuum fluctuations on the thermodynamics and phase diagram. The resulting model predictions are compared to the recent QCD lattice simulations by the HotQCD and Wuppertal-Budapest collaborations. The variation of the thermodynamic quantities across the phase transition region becomes smoother. This results in better agreement with the lattice data. Depending on the value of the mass of the sigma meson, including the vacuum term results in either pushing the critical end point into higher values of the chemical potential or excluding the possibility of a critical end point altogether.