Dual Formulation and Phase Diagram of Lattice QCD in the Strong Coupling Regime

TL;DR

This paper develops a dual formulation for lattice QCD in the strong coupling regime, enabling better Monte Carlo simulations at finite density and mapping the phase diagram including gauge corrections.

Contribution

It introduces a method to evaluate complex gauge integrals for gauge corrections and establishes the phase boundary in the strong coupling limit with higher order corrections.

Findings

Phase boundary of lattice QCD in the strong coupling limit determined.

Method for evaluating gauge integrals with corrections developed.

Numerical simulations show the impact of gauge corrections on the phase diagram.

Abstract

We present the computation of invariants that arise in the strong coupling expansion of lattice QCD. These invariants are needed for Monte Carlo simulations of Lattice QCD with staggered fermions in a dual, color singlet representation. This formulation is in particular useful to tame the finite density sign problem. The gauge integrals in this limiting case $\beta\rightarrow 0$ are well known, but the gauge integrals needed to study the gauge corrections are more involved. We discuss a method to evaluate such integrals. The phase boundary of lattice QCD for staggered fermions in the $\mu_B-T$ plane has been established in the strong coupling limit. We present numerical simulations away from the strong coupling limit, taking into account the higher order gauge corrections via plaquette occupation numbers. This allows to study the nuclear and chiral transition as a function of $\beta$.