Topological susceptibility in Lattice QCD with unimproved Wilson fermions

TL;DR

This paper investigates the behavior of topological susceptibility in lattice QCD with unimproved Wilson fermions, demonstrating its suppression with decreasing quark mass across different lattice spacings and volumes.

Contribution

It provides the first unambiguous confirmation of topological susceptibility suppression in unimproved Wilson fermions through systematic lattice simulations.

Findings

Suppression of topological susceptibility with decreasing quark mass.

Effect of lattice spacing and volume on topological sectors.

Confirmation aligns with chiral Ward identity and chiral perturbation theory.

Abstract

We address a long standing problem regarding topology in lattice simulations of QCD with unimproved Wilson fermions. Earlier attempt with unimproved Wilson fermions at \beta =5.6 to verify the suppression of topological susceptibility with decreasing quark mass (m_q) was unable to unambiguously confirm the suppression. We carry out systematic calculations for two degenerate flavours at two different lattice spacings (\beta = 5.6 and 5.8). The effects of quark mass, lattice volume and the lattice spacing on the spanning of different topological sectors are presented. We unambiguously demonstrate the suppression of the topological susceptibility with decreasing quark mass, expected from chiral Ward identity and chiral perturbation theory.