Topology of dynamical lattice configurations including results from dynamical overlap fermions

TL;DR

This study compares topological charge densities in lattice QCD simulations across various fermion actions, including overlap fermions, revealing minimal differences in topological observables at current lattice spacings.

Contribution

It provides a systematic comparison of topological properties in lattice QCD with different fermion actions, highlighting the consistency of topological observables.

Findings

Core size scales linearly with lattice spacing across actions.

Different actions vary by about 10% in subleading terms.

Non-chiral actions show similar topological features as overlap fermions.

Abstract

We investigate how the topological charge density in lattice QCD simulations is affected by violations of chiral symmetry caused by the fermion action. To this end we compare lattice configurations generated with a number of different actions including first configurations generated with exact dynamical overlap quarks. We visualize the topological profiles after mild smearing. In the topological charge correlator we measure the size of the positive core, which is known to shrink to zero extension in the continuum limit. To leading order we find the core size to scale linearly with the lattice spacing with the same coefficient for all actions, even including quenched simulations. In the subleading term the different actions vary over a range of about 10 %. Our findings suggest that non-chiral lattice actions at current lattice spacings do not differ much for observables related to topology, both among themselves and compared to overlap fermions.