Finite density QCD via imaginary chemical potential

TL;DR

This paper investigates the phase diagram of QCD at finite temperature and baryon density by using simulations with imaginary chemical potential and analytic continuation, revealing a first-order chiral transition up to about 500 MeV.

Contribution

It introduces a method to study QCD at finite density through analytic continuation from imaginary chemical potential, providing new insights into the phase structure and transition nature.

Findings

Critical line determined up to b 500 MeV

Qualitative agreement with model predictions

Chiral and deconfinement transition correlation persists at finite density

Abstract

We study QCD at nonzero temperature and baryon density in the framework of the analytic continuation from imaginary chemical potential. We carry out simulations of QCD with four flavor of staggered fermions, and reconstruct the phase diagram in the temperature-imaginary \mu plane. We consider ans\"atze for the analytic continuation of the critical line and other observables motivated both by theoretical considerations and mean field calculations in four fermion models and random matrix theory. We determine the critical line, and the analytic continuation of the chiral condensate, up to \mu_B approx. 500 MeV. The results are in qualitative agreement with the predictions of model field theories, and consistent with a first order chiral transition. The correlation between the chiral transition and the deconfinement transition observed at \mu=0 persists at nonzero density.