Topological Summation of Observables Measured with Dynamical Overlap Fermions

TL;DR

This paper investigates methods to accurately combine measurements of physical observables taken in different topological sectors in lattice QCD simulations with dynamical overlap fermions, addressing sampling issues caused by topological freezing.

Contribution

It explores and evaluates techniques for summing observables across topological sectors in dynamical overlap fermion simulations, improving data analysis methods.

Findings

Identified effective summation techniques for topological sectors.

Applied methods to chiral condensate and pion mass data.

Enhanced understanding of topological effects in lattice simulations.

Abstract

HMC histories for light dynamical overlap fermions tend to stay in a fixed topological sector for many trajectories, so that the different sectors are not sampled properly. Therefore the suitable summation of observables, which have been measured in separate sectors, is a major challenge. We explore several techniques for this issue, based on data for the chiral condensate and the (analogue of the) pion mass in the 2-flavour Schwinger model with dynamical overlap-hypercube fermions.