The FLIC Overlap Quark Propagator

TL;DR

This paper compares the FLIC overlap fermion propagator with the Wilson overlap in quenched QCD, analyzing their structure, scaling, and discretisation errors across different lattice spacings and quark masses.

Contribution

It introduces and studies the FLIC overlap fermion propagator, highlighting its improved performance and scaling properties over the Wilson overlap in certain regimes.

Findings

FLIC overlap and Wilson overlap agree at light quark masses in infrared and ultraviolet.

Disagreement appears at heavier masses in the ultraviolet, due to different discretisation errors.

Both actions show reasonable scaling with some violations.

Abstract

FLIC overlap fermions are a variant of the standard (Wilson) overlap action, with the FLIC (Fat Link Irrelevant Clover) action as the overlap kernel rather than the Wilson action. The structure of the FLIC overlap fermion propagator in momentum space is studied, and a comparison against previous studies of the Wilson overlap propagator in quenched QCD is performed. To explore the scaling properties of the propagator for the two actions, numerical calculations are performed in Landau Gauge across three lattices with different lattice spacing $a$ and similar physical volumes. We find that at light quark masses the acti ons agree in both the infrared and the ultraviolet, but at heavier masses some disagreement in the ultraviolet appears. This is attributed to the two action s having different discretisation errors with the FLIC overlap providing superior performance in this regime. Both actions scale reasonably, but some scaling violations are observed.