Features of a 2d Gauge Theory with Vanishing Chiral Condensate

TL;DR

This paper investigates a 2D gauge theory with two light flavors, focusing on its zero chiral condensate and IR conformal properties, using lattice simulations to test theoretical predictions and explore low eigenvalue behavior.

Contribution

It provides numerical evidence and analysis of the chiral properties and IR behavior of the 2D gauge theory with vanishing chiral condensate, highlighting subtleties in interpreting low eigenvalues.

Findings

Low lying Dirac eigenvalues show specific decorrelation patterns.

Mass anomalous dimension behavior is analyzed and discussed.

Subtleties in IR extrapolation are identified, cautioning similar studies.

Abstract

The Schwinger model with $N_f \geq 2$ flavors is a simple example for a fermionic model with zero chiral condensate Sigma (in the chiral limit). We consider numerical data for two light flavors, based on simulations with dynamical chiral lattice fermions. We test properties and predictions that were put forward in the recent literature for models with Sigma = 0, which include IR conformal theories. In particular we probe the decorrelation of low lying Dirac eigenvalues, and we discuss the mass anomalous dimension and its IR extrapolation. Here we encounter subtleties, which may urge caution with analogous efforts in other models, such as multi-flavor QCD.