Numerical study of the equation of state for two flavor QCD at finite density

TL;DR

This study numerically investigates the equation of state for two-flavor QCD at finite temperature and density, revealing critical behavior and susceptibilities that suggest a critical endpoint in the phase diagram.

Contribution

It provides a numerical analysis of the QCD equation of state at finite density using Taylor expansion, highlighting the behavior near the phase transition.

Findings

Quark number density fluctuations increase near the transition temperature.

Susceptibilities develop a peak with increasing chemical potential.

Evidence suggests a critical endpoint in the phase diagram.

Abstract

We discuss the equation of state for 2 flavor QCD at non-zero temperature and density. Derivatives of $\ln Z$ with respect to quark chemical potential $\mu_q$ up to fourth order are calculated, enabling estimates of the pressure, quark number density and associated susceptibilities as functions of $\mu_q$ via a Taylor series expansion. It is found that the fluctuations in the quark number density increase in the vicinity of the phase transition temperature and the susceptibilities start to develop a pronounced peak as $\mu_q$ is increased. This suggests the presence of a critical endpoint in the $(T, \mu_q)$ plane.