The impact of localized overlap eigenmodes on RMT measurements and topology

TL;DR

This paper investigates how localized eigenmodes in lattice QCD Dirac operators, caused by discretization effects, influence measurements of topology and chiral symmetry, highlighting the dependence on operator parameters.

Contribution

It analyzes the impact of localized eigenmodes on RMT and topological measurements, providing insights into lattice artifacts and their parameter dependence.

Findings

Localized eigenmodes affect topological susceptibility measurements.

Discretization effects induce non-physical modes impacting chiral observables.

Parameter tuning can mitigate lattice artifacts.

Abstract

The low energy eigenmodes of the continuum QCD Dirac operator are extended, but on the lattice, due to discretization effects, the Dirac operator can have localized eigenmodes. These non-physical modes can introduce strong lattice artifacts for observables that are sensitive to chiral symmetry, especially in mixed action simulations. We study how these lattice artifacts depend on the parameters of the overlap operator and their affect on the distribution on the Dirac eigenmodes and the topological susceptibility.