Overlap Quark Propagator in Landau Gauge

TL;DR

This study investigates the Landau gauge quark propagator in quenched QCD using overlap fermions, revealing dynamical mass generation and providing nonperturbative functions for various bare masses.

Contribution

It presents the first nonperturbative calculation of the Landau gauge quark propagator with overlap fermions on a lattice, demonstrating chiral symmetry and infrared mass generation.

Findings

Observation of dynamical infrared mass generation

Extraction of nonperturbative wavefunction renormalization and mass functions

Confirmation of qualitative behavior of Landau gauge quark propagator

Abstract

The properties of the quark propagator in Landau gauge in quenched QCD are examined for the overlap quark action. The overlap quark action satisfies the Ginsparg-Wilson relation and as such provides an exact lattice realization of chiral symmetry. This in turn implies that the quark action is free of ${\cal O}(a)$ errors. We present results using the standard Wilson fermion kernel in the overlap formalism on a $12^3\times 24$ lattice at a spacing of 0.125 fm. We obtain the nonperturbative momentum-dependent wavefunction renormalization function $Z(p)$ and the nonperturbative mass function $M(p)$ for a variety of bare masses. We perform a simple extrapolation to the chiral limit for these functions. We clearly observe the dynamically generated infrared mass and confirm the qualitative behavior found for the Landau gauge quark propagator in earlier studies. We attempt to extract the quark condensate from the asymptotic behavior of the mass function in the chiral limit.