Simulating full QCD at nonzero density using the complex Langevin equation

TL;DR

This paper extends the complex Langevin method to simulate full QCD at non-zero density, demonstrating stabilization techniques and agreement with approximations, enabling high-density simulations up to saturation.

Contribution

The paper introduces gauge cooling to stabilize complex Langevin simulations for full QCD at finite density and compares results with HQCD, showing good agreement.

Findings

Gauge cooling stabilizes simulations at small lattice spacings.

Results agree with HQCD at large fermion mass.

Simulations are feasible at high densities up to saturation.

Abstract

The complex Langevin method is extended to full QCD at non-zero chemical potential. The use of gauge cooling stabilizes the simulations at small enough lattice spacings. At large fermion mass the results are compared to the HQCD approach, in which the spatial hoppings of fermionic variables are neglected, and good agreement is found. The method allows simulations also at high densities, all the way up to saturation.