Testing UV-filtered ("fat-link") clover fermions

TL;DR

This paper explores the use of various filtering techniques on clover fermions with fat gauge links, demonstrating reduced chiral symmetry breaking through theoretical and numerical analysis.

Contribution

It introduces and compares multiple filtering recipes for clover fermions, showing their effectiveness in reducing chiral symmetry breaking in both theory and simulations.

Findings

Filtered fermions exhibit significantly less chiral symmetry breaking.

Certain filtering recipes are compatible with HMC for dynamical fermions.

Numerical results confirm theoretical predictions.

Abstract

We investigate filtered clover fermions, built from fat gauge links, both in one-loop perturbation theory and in numerical simulations. We use a variety of filtering recipes (APE, HYP, EXP, HEX), some of which are suitable for a HMC with dynamical fermions. A generic filtering together with a (fat-link) clover term yields fermions with much reduced chiral symmetry breaking.