Staggered versus overlap fermions: a study in the Schwinger model with $N_f=0,1,2$

TL;DR

This paper compares overlap and staggered fermions in the Schwinger model, analyzing scalar condensate and topological susceptibility across different flavors and quark masses, highlighting discretization effects and their reduction through smearing.

Contribution

It provides a detailed comparison of overlap and staggered fermions in the Schwinger model, focusing on their behavior near the chiral limit and the impact of smearing.

Findings

Differences between formulations are dramatic near the chiral limit at finite lattice spacing.

Smearing reduces the discretization differences significantly.

Discretization effects depend on the number of flavors and quark masses.

Abstract

We study the scalar condensate and the topological susceptibility for a continuous range of quark masses in the Schwinger model with $N_f=0,1,2$ dynamical flavors, using both the overlap and the staggered discretization. At finite lattice spacing the differences between the two formulations become rather dramatic near the chiral limit, but they get severely reduced, at the coupling considered, after a few smearing steps.