The QCD Phase Diagram with Effective Theories

TL;DR

This paper develops and applies effective theories for QCD at finite temperature and chemical potential, solving the sign problem to enable Monte Carlo simulations of the phase diagram.

Contribution

It introduces two effective models using Polyakov loops that are free of the sign problem, allowing detailed exploration of the QCD phase diagram.

Findings

Successful Monte Carlo simulations of the models

Mapping of the partition function to positive weights

Determination of the phase diagram across temperature and chemical potential

Abstract

We study two effective theories for QCD at non-zero temperature and finite chemical potential, using local Polyakov loops as the degrees of freedom. The sign problem is solved by exactly mapping the partition function to a sum over flux and monomer variables with only real and positive weights, making the two models accessible to Monte Carlo simulation techniques. We use generalized worm algorithms and a local Metropolis update to perform the simulations and determine the phase diagram as a function of the temperature and the chemical potential.