Instanton liquid properties from lattice QCD

TL;DR

This paper investigates the properties of instantons in lattice QCD configurations with various quark flavors using two complementary methods: Gradient flow analysis and gluon Green's functions, providing insights into the instanton liquid model.

Contribution

It introduces a dual-approach methodology combining Gradient flow and gluon Green's functions to analyze instanton properties in lattice QCD with different quark flavors.

Findings

Consistent instanton densities obtained from both methods.

Evolution of instanton properties with flow time analyzed.

Confirmation of instanton contributions to low-momentum gluon Green's functions.

Abstract

We examined the instanton contribution to the QCD configurations generated from lattice QCD for $N_F=0$, $N_F=2+1$ and $N_F=2+1+1$ dynamical quark flavors from two different and complementary approaches. First via the use of Gradient flow, we computed instanton liquid properties using an algorithm to localize instantons in the gauge field configurations and studied their evolution with flow time. Then, the analysis of the running at low momenta of gluon Green's functions serves as an independent confirmation of the instanton density which can also be derived without the use of the Gradient flow.