Finite-density equation of state of hot QCD using the complex Langevin equation

TL;DR

This paper uses complex Langevin simulations to determine the QCD equation of state at high baryon densities and temperatures, extending previous studies and confirming results with perturbative calculations.

Contribution

First continuum-extrapolated lattice QCD results at high baryon densities using complex Langevin dynamics at the physical point.

Findings

Agreement with previous lattice studies at smaller chemical potentials

Consistency with perturbative calculations at high temperatures

Successful control of potential convergence issues in complex Langevin simulations

Abstract

We present the results of continuum-extrapolated lattice simulations of quantum chromodynamics (QCD) above the crossover temperature and for unprecedentedly high baryon densities at the physical point, employing the complex Langevin equation. In particular, we determine the QCD equation of state by computing the baryon density as well as the pressure as functions of the baryon chemical potential and the temperature. Potential issues with wrong convergence of complex Langevin dynamics are under control and we indeed find agreement with previous lattice studies working at smaller chemical potentials, as well as with perturbative hard-thermal-loop calculations at high temperatures.