Status of Lattice Studies of the QCD Phase Diagram

TL;DR

This paper reviews the current status of lattice QCD calculations of the phase diagram, highlighting that the transition remains a crossover at low baryon chemical potential and challenging earlier predictions of a critical point.

Contribution

It provides an updated overview of lattice results for the QCD phase diagram at low chemical potentials, emphasizing the persistence of crossover behavior.

Findings

Crossover transition at =0 in the continuum limit.

Evidence suggests the crossover weakens with increasing _B, not turning into a critical point.

Lattice results challenge earlier predictions of a critical point in the phase diagram.

Abstract

Determining the QCD phase diagram is a pressing task in view of its relevance for nuclear and astro-particle physics programmes. We review the current status of lattice calculations of the phase diagram in the (T,\mu_B)-plane for baryon chemical potentials \mu_B < 500 MeV. At \mu_B=0, simulations of staggered fermion actions predict the quark hadron transition to be a crossover in the continuum limit. As a baryon chemical potential is turned on, there is mounting evidence on coarse lattices for the crossover to weaken, rather than turning into a true phase transition at a critical point, as predicted by earlier simulations.