The $N_f= 2$ chiral phase transition from imaginary chemical potential with Wilson Fermions

TL;DR

This study investigates the nature of the chiral phase transition in two-flavor QCD using Wilson fermions at imaginary chemical potential, finding a large first order transition region at finite lattice spacing.

Contribution

First to analyze the chiral phase transition with Wilson fermions at imaginary chemical potential, providing evidence of a large first order region.

Findings

Large first order transition region observed with Wilson fermions.

Supports the scenario of a first order transition in the continuum limit.

Contrasts with previous staggered fermion results at finite temperature.

Abstract

The order of the thermal transition in the chiral limit of QCD with two dynamical flavours of quarks is a long-standing issue. Still, it is not definitely known whether the transition is of first or second order in the continuum limit. Which of the two scenarios is realized has important implications for the QCD phase diagram and the existence of a critical endpoint at finite densities. Settling this issue by simulating at successively decreased pion mass was not conclusive yet. Recently, an alternative approach was proposed, extrapolating the first order phase transition found at imaginary chemical potential to zero chemical potential with known exponents, which are induced by the Roberge-Weiss symmetry. For staggered fermions on $N_t=4$ lattices, this results in a first order transition in the chiral limit. Here we report of $N_t=4$ simulations with Wilson fermions, where the first order region is found to be large.