Recent developments at finite density on the lattice

TL;DR

This paper reviews recent computational methods to address the numerical sign problem in lattice QCD at finite density, including techniques like changing integration order, density of states, and complex plane extensions.

Contribution

It introduces and discusses recent advances such as integration order modification, density of states, and complex Langevin and Lefschetz thimbles methods for tackling the sign problem.

Findings

Improved techniques reduce the severity of the sign problem.

Extensions into the complex plane enable new computational approaches.

These methods enhance the feasibility of simulating QCD at nonzero density.

Abstract

Some recent developments to handle the numerical sign problem in QCD and related theories at nonzero density are reviewed. In this contribution I focus on changing the integration order to soften the severity of the sign problem, the density of states, and the extension into the complex plane (complex Langevin dynamics and Lefshetz thimbles).