Unquenching the topological susceptibility with an overlap action

TL;DR

This paper investigates how the topological susceptibility in quantum chromodynamics depends on quark mass using dynamical overlap and clover fermions, revealing that current simulations may not fully capture expected suppression due to chiral symmetry breaking.

Contribution

It introduces a reweighting method with low-eigenmode truncation to estimate unquenching effects on topological susceptibility in lattice QCD.

Findings

Unquenching effects are well approximated by reweighting with low-eigenmode truncation.

Current dynamical simulations do not show the expected suppression due to explicit chiral symmetry breaking.

The explicit chiral symmetry breaking of fermion actions impacts topological susceptibility measurements.

Abstract

We estimate the quark-mass dependence of the topological susceptibility with dynamical overlap and clover fermions. Unquenching effects on the susceptibility turn out to be well approximated by a reweighting of a quenched ensemble with a low-eigenmode truncation of the fermionic determinant. We find that it is most likely due to the explicit chiral symmetry breaking of the fermion action that present day dynamical simulations do not show the expected suppression of the topological susceptibility.