Reconstructing the gluon

TL;DR

This paper reconstructs the gluon spectral function in Landau gauge QCD using novel analytical and basis construction methods, enabling reliable analysis of the non-perturbative gluon spectrum.

Contribution

It introduces a new approach combining analytical low-frequency asymptotics and a specialized functional basis for spectral reconstruction in Landau gauge QCD.

Findings

Successfully reconstructs the gluon spectral function.

Analyzes systematic errors of different methods.

Provides insights into the non-perturbative gluon regime.

Abstract

We reconstruct the gluon spectral function in Landau gauge QCD from numerical data for the gluon propagator. The reconstruction relies on two novel ingredients: Firstly we derive analytically the low frequency asymptotics of the spectral function. Secondly we construct a functional basis from a careful consideration of the analytic properties of the gluon propagator in Landau gauge. This allows us to reliably capture the non-perturbative regime of the gluon spectrum. We also compare different reconstruction methods and discuss the respective systematic errors.