Topology of dynamical lattice configurations including results from dynamical overlap fermions

TL;DR

This paper compares how different lattice QCD fermion actions affect topological charge density, finding that non-chiral actions produce similar results to overlap fermions at current lattice spacings, especially in the topological charge correlator.

Contribution

It provides a comparative analysis of topological charge density across various fermion actions, including exact overlap quarks, highlighting their similarities at practical lattice spacings.

Findings

Core size scales linearly with lattice spacing across actions.

Different actions vary by about 10% in subleading terms.

Non-chiral actions yield results close to overlap fermions at current spacings.

Abstract

We investigate how the topological charge density in lattice QCD simulations is affected by violations of chiral symmetry in different fermion actions. To this end we compare lattice configurations generated with a number of different actions including first configurations generated with exact 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 vanish 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 this specific observable related to topology, both among themselves and compared to overlap fermions.