Critical point search from an extended parameter space of lattice QCD at finite temperature and density

TL;DR

This study explores the phase structure of lattice QCD at finite temperature and density by analyzing the effects of varying flavor numbers, quark masses, and chemical potential through simulations and reweighting methods.

Contribution

It introduces a novel approach to map the critical surface in extended parameter space of lattice QCD, including multiple flavors and finite density effects.

Findings

Identified the critical surface terminating first order phase transitions.

Mapped the phase structure of QCD with multiple flavors at finite density.

Demonstrated the effectiveness of reweighting in exploring parameter space.

Abstract

Aiming to understand the phase structure of lattice QCD at nonzero temperature and density, we study the phase transitions of QCD in an extended parameter space, where the number of flavor and quark masses are considered as parameters. Performing simulations of 2 flavor QCD and using the reweighting method, we investigate (2+Nf) flavor QCD at finite density, where two light flavors and Nf massive flavors exist. Calculating probability distribution functions, we determine the critical surface terminating first order phase transitions in the parameter space of the light quark mass, the heavy quark mass and the chemical potential. Through the study of the many flavor system, we discuss the phase structure of QCD at finite density.