Dirac spectral density and mass anomalous dimension in 2+1 flavor QCD

TL;DR

This paper calculates the Dirac spectral density in 2+1 flavor QCD using lattice simulations and compares the results with high-order perturbation theory to understand non-perturbative effects.

Contribution

It introduces a stochastic method to compute the spectral density across a wide eigenvalue range and estimates the continuum limit using multiple lattice spacings.

Findings

Spectral density matches perturbative predictions at high eigenvalues

Discretization effects minimized with generalized valence domain-wall fermions

Provides continuum extrapolation of spectral density in 2+1 flavor QCD

Abstract

We compute the Dirac spectral density of QCD in a wide range of eigenvalues by using a stochastic method. We use 2+1 flavor lattice ensembles generated with Mobius domain-wall fermion at three lattice spacings ($a=0.083, 0.055, 0.044$ fm) to estimate the continuum limit. The discretization effect can be minimized by a generalization of the valence domain-wall fermion. The spectral density at relatively high eigenvalues can be matched with perturbation theory. We compare the lattice results with the perturbative expansion available to $O(\alpha_s^4)$.