Critical point of $N_f = 3$ QCD from lattice simulations in the canonical ensemble

TL;DR

This study uses lattice simulations in the canonical ensemble to locate the critical point of three-flavor QCD, identifying phase boundaries and the critical temperature and chemical potential with improved lattice techniques.

Contribution

The paper introduces a canonical ensemble lattice simulation method with Fourier transform of the fermion determinant to precisely locate the QCD critical point.

Findings

Critical point at T_E = 0.925(5) T_c

Critical chemical potential at μ_B^E = 2.60(8) T_c

Phase boundaries determined at three temperatures

Abstract

A canonical ensemble algorithm is employed to study the phase diagram of $N_f = 3$ QCD using lattice simulations. We lock in the desired quark number sector using an exact Fourier transform of the fermion determinant. We scan the phase space below $T_c$ and look for an S-shape structure in the chemical potential, which signals the coexistence phase of a first order phase transition in finite volume. Applying Maxwell construction, we determine the boundaries of the coexistence phase at three temperatures and extrapolate them to locate the critical point. Using an improved gauge action and improved Wilson fermions on lattices with a spatial extent of $1.8 \fm$ and quark masses close to that of the strange, we find the critical point at $T_E = 0.925(5) T_c$ and baryon chemical potential $\mu_B^E = 2.60(8) T_c$.