The equation of state of QCD at finite chemical potential

TL;DR

This paper computes the equation of state of QCD at finite chemical potential using lattice simulations, providing insights into baryon density, pressure, and compressibility with controlled error estimates.

Contribution

It introduces a resummation method for Taylor series in lattice QCD to reliably estimate thermodynamic quantities at finite chemical potential.

Findings

Baryon density and pressure are insensitive to quark mass.

Provides estimates of the bulk isothermal compressibility across T and mu_B.

Method yields controlled error bounds for resummed quantities.

Abstract

We obtain the baryon number density, n, and the excess contribution to the pressure, Delta P, at finite chemical potential, mu_B, and temperature, T, by resumming the Taylor series expansion in a lattice computation with lattice spacing of 1/(4T) and two flavours of quarks at three different quark masses. The method proceeds by giving a critical mu_B and limits on the critical exponent, and permits reliable estimations of the errors in resummed quantities. We find that n and Delta P are insensitive to the quark mass. We also report the bulk isothermal compressibility, kappa, over a range of T and mu_B.