Critical point in finite density lattice QCD by canonical approach

TL;DR

This paper introduces a Monte Carlo-based method to locate the QCD critical point at finite density by analyzing the canonical partition function, revealing a phase transition at low temperature and high density.

Contribution

It presents a novel approach to identify the QCD critical point using canonical partition functions calculated via lattice QCD simulations.

Findings

Effective potential shape changes with temperature.

First order phase transition observed at low T and high density.

Evidence suggests the existence of the QCD critical point.

Abstract

We propose a method to find the QCD critical point at finite density calculating the canonical partition function ${\cal Z}_{\rm C} (T,N)$ by Monte-Carlo simulations of lattice QCD, and analyze data obtained by a simulation with two-flavor p4-improved staggered quarks with pion mass $m_{\pi} \approx 770 {\rm MeV}$. It is found that the shape of an effective potential changes gradually as the temperature decreases and a first order phase transition appears in the low temperature and high density region. This result strongly suggests the existence of the critical point in the $(T, \mu_q)$ phase diagram.