The High Density Region of QCD from an Effective Model

TL;DR

This paper investigates the phase structure of high-density QCD using an effective model based on Polyakov loops, exploring how observables change with chemical potential and temperature to infer possible phase transitions.

Contribution

It introduces a new effective model for high-density QCD that addresses the sign problem and analyzes phase transitions using Monte Carlo simulations.

Findings

Charge density increases with chemical potential.

Polyakov loop susceptibility indicates phase transitions.

Model provides insights into QCD phase structure at high density.

Abstract

We study the high density region of QCD within an effective model obtained in the frame of the hopping parameter expansion and choosing Polyakov-type loops as the main dynamical variables representing the fermionic matter. This model still shows the so-called sign problem, a difficulty peculiar to non-zero chemical potential, but it permits the development of algorithms which ensure a good overlap of the simulated Monte Carlo ensemble with the true one. We review the main features of the model and present results concerning the dependence of various observables on the chemical potential and on the temperature, in particular of the charge density and the Polykov loop susceptibility, which may be used to characterize the various phases expected at high baryonic density. In this way, we obtain information about the phase structure of the model and the corresponding phase transitions and cross over regions, which can be considered as hints about the behaviour of non-zero density QCD.