Lattice QCD at finite temperature and density

TL;DR

This paper introduces a novel numerical method combining cumulant expansion and reweighting to study QCD phase transitions at finite temperature and density, effectively addressing the sign problem in lattice simulations.

Contribution

It proposes a new approach to circumvent the sign problem in lattice QCD at finite density, enabling the investigation of the critical point and phase structure.

Findings

Identification of the critical point in lattice QCD at high temperature and density

Demonstration of the method's effectiveness in avoiding the sign problem

Insights into the phase transition line in the QCD phase diagram

Abstract

We study the phase structure of QCD at finite temperature and density by numerical simulations on a lattice. The most important point for the numerical study at finite density is treatment of the sign problem. We propose a method to avoid the sign problem, which is based on a cumulant expansion of the complex phase in the density of state method combined with the reweighting method. Using the method, we study the critical point terminating a first order phase transition line in lattice QCD at high temperature and density.