Quenched QCD at finite temperature with chiral Fermions

TL;DR

This study investigates the behavior of chiral fermions in quenched lattice QCD at temperatures near the QCD phase transition, revealing insights into symmetry restoration and screening masses.

Contribution

It provides new insights into the fate of axial U(1) symmetry and chiral symmetry restoration at finite temperature using overlap fermions.

Findings

Zero modes are localized and decrease with temperature.

Axial U(1) symmetry remains broken up to 2Tc.

Chiral symmetry is restored after zero mode subtraction.

Abstract

We study physics at temperatures just above the QCD phase transition (Tc) using chiral (overlap) Fermions in the quenched approximation of lattice QCD. Exact zero modes of the overlap Dirac operator are localized and their frequency of occurrence drops with temperature. This is closely related to axial U(1) symmetry, which remains broken up to 2Tc. After subtracting the effects of these zero modes, chiral symmetry is restored, as indicated by the behavior of the chiral condensate. The pseudoscalar and vector screening masses are close to ideal gas values.