Lee-Yang zeros in lattice QCD for searching phase transition points

TL;DR

This paper investigates the distribution of Lee-Yang zeros in lattice QCD at finite temperature and density to identify phase transition points, utilizing quark number densities at imaginary chemical potential and analyzing their temperature dependence.

Contribution

It introduces a method to estimate Lee-Yang zeros in lattice QCD by fitting quark number densities at imaginary chemical potential, enabling the study of phase transitions without sign problem complications.

Findings

Observation of Roberge-Weiss phase transition at T/T_c >= 1.20

Distribution of Lee-Yang zeros varies with temperature around the pseudo-critical point

Method allows estimation of infinite volume limit for Lee-Yang zeros

Abstract

We report Lee-Yang zeros behavior at finite temperature and density. The quark number densities, <n>, are calculated at the pure imaginary chemical potential, where no sign problem occurs. Then, the canonical partition functions, Z_C(n,T,V), up to some maximal values of n are estimated through fitting theoretically motivated functions to <n>, which are used to compute the Lee-Yang zeros. We study the temperature dependence of the distributions of the Lee-Yang zeros around the pseudo-critical temperature region T/T_c = 0.84 - 1.35. In the distributions of the Lee-Yang zeros, we observe the Roberge-Weiss phase transition at T/T_c >= 1.20. We discuss the dependence of the behaviors of Lee-Yang zeros on the maximal value of n, so that we can estimate a reliable infinite volume limit.