Mixed Action Simulations on Staggered Background; Interpretation and Result for the 2-flavor QCD Chiral Condensate

TL;DR

This study examines the validity of staggered fermion simulations in lattice QCD by comparing eigenmode distributions to continuum predictions, finding consistency with 2-flavor QCD and estimating the chiral condensate.

Contribution

It demonstrates that staggered configurations can accurately reproduce continuum QCD properties with minimal lattice artifacts at specific quark masses.

Findings

Staggered configurations align with continuum QCD predictions.

A matching quark mass minimizes lattice corrections.

Estimated chiral condensate is consistent with theoretical expectations.

Abstract

Growing evidence indicates that in the continuum limit the rooted staggered action is in the correct QCD universality class, the non-local terms arising from taste breaking can be viewed as lattice artifacts. In this paper we consider the 2-flavor Asqtad staggered action at a lattice spacing of approximately 0.13 fm and probe the properties of the staggered configurations by an overlap valence Dirac operator. By comparing the distribution of the overlap eigenmodes to continuum QCD predictions we investigate if/when the lattice artifacts are small as a function of the staggered quark mass. We define a matching overlap quark mass where the lattice corrections are minimal for the topological susceptibility and from the eigenmode distribution we predict the 2-flavor chiral condensate. Our results indicate that the staggered configurations are consistent with 2-flavor continuum QCD up to small lattice artifacts, and predict a consistent value for the infinite volume chiral condensate.