Analyticity and the phase diagram of QCD

TL;DR

This paper explores the implications of analyticity in QCD's free energy at finite chemical potential, proposing a novel numerical method using imaginary chemical potential to map the phase diagram and analyze phase transitions.

Contribution

It introduces a new approach leveraging analyticity and imaginary chemical potential simulations to study the QCD phase diagram and Yang-Lee zeroes.

Findings

Method for numerical exploration of QCD phase diagram

Use of imaginary chemical potential to extract Yang-Lee zeroes

Discussion on symmetries and susceptibilities in QCD

Abstract

Some consequences of the analyticity of the free energy (pressure) of QCD at finite chemical potential are deduced. These include a method for numerical exploration of the full phase diagram by a novel use of simulations at imaginary chemical potential to extract Yang-Lee zeroes of the grand-canonical partition function. We make use of, and comment on, CPT symmetries, positivity of non-linear susceptibilities and the finiteness of screening lengths. We also comment on the structure of zeroes expected for the usual picture of the phases of QCD, following a discussion of the physics of imaginary chemical potential.