The Equation of State for Two Flavor QCD at Non-zero Chemical Potential

TL;DR

This paper investigates the thermodynamic properties of two-flavor QCD at non-zero chemical potential using lattice simulations, calculating derivatives of the grand potential to estimate pressure, density, and susceptibilities, and discussing discretization effects and convergence.

Contribution

It introduces a method to compute thermodynamic quantities of QCD at finite chemical potential using Taylor expansion and analyzes discretization effects and convergence radius.

Findings

Calculated derivatives of grand potential up to fourth order.

Estimated pressure, density, and susceptibilities as functions of chemical potential.

Discussed discretization effects and convergence properties.

Abstract

We present results of a simulation of QCD on a 4x16^3 lattice with 2 continuum flavors of p4-improved staggered fermion with mass m/T=0.4. Derivatives of the thermodynamic grand potential 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 Taylor series expansion. Discretisation effects associated with various staggered fermion formulations are discussed in some detail. In addition it is possible to estimate the radius of convergence of the expansion as a function of temperature. We also discuss the calculation of energy and entropy densities which are defined via mixed derivatives of the thermodynamic grand potential with respect to the bare couplings and quark masses.