Continuous Time Simulations of Strong Coupling LQCD at Finite Baryon Density

TL;DR

This paper introduces a sign problem free continuous time lattice QCD simulation method at finite baryon density, enabling comprehensive exploration of the phase diagram and precise calculation of thermodynamic quantities.

Contribution

It develops a novel non-perturbative continuous time lattice QCD approach at infinite gauge coupling, allowing detailed study of the entire baryon chemical potential-temperature plane.

Findings

Sign problem is eliminated in the continuous time framework.

Taylor coefficients for pressure expansion are successfully computed.

Baryon number cumulants are measured with improved accuracy.

Abstract

We study lattice QCD in the limit of infinite gauge coupling on a discrete spatial yet continuous Euclidean time lattice at finite baryon chemical potential $\mu_B$. The continuous time framework is based on sending $N_\tau\rightarrow \infty$ and the bare anisotropy to infinity while fixing the temperature in a non-perturbative setup. This leads to a sign problem free algorithm that allows us to study the whole $\mu_B$-$T$ plane. We construct Taylor coefficients required for a Taylor expansion in the pressure at zero chemical potential and in the chiral limit. On that account, cumulants in the baryon number density are measured in various fashions to improve on accuracy. These calculations are based on our worm type Monte Carlo algorithm featuring a polymer resummation scheme and a histogram method.