Role of the Wilson mass parameter in the overlap Dirac topological charge density

TL;DR

This paper investigates how the choice of the negative Wilson mass parameter affects the topological charge density in the overlap Dirac operator, revealing a significant dependence similar to smearing effects in gluonic definitions.

Contribution

It demonstrates that the Wilson mass parameter introduces a controllable freedom in the overlap formalism, akin to smearing in gluonic approaches, impacting topological charge density measurements.

Findings

Strong dependence of topological charge density on Wilson mass parameter

Correlation between overlap and gluonic definitions with smearing

Wilson mass parameter acts as a smearing-like degree of freedom

Abstract

The negative Wilson mass parameter is an input parameter to the overlap Dirac operator. We examine the extent to which the topological charge density, revealed by the overlap definition, depends on the value of the negative Wilson mass. A strong dependence is observed, which can be correlated with the topological charge density obtained from the gluonic definition, with a variable number of stout-link smearing sweeps. The results indicate that the freedom typically associated with fat-link fermion actions, through the number of smearing sweeps, is also present in the overlap formalism, through the freedom in the Wilson mass parameter.