Another look at the Landau-gauge gluon and ghost propagators at low momentum

TL;DR

This study investigates how the low-momentum behavior of gluon and ghost propagators in SU(2) lattice Landau gauge theory depends on the Faddeev-Popov operator's eigenvalues, revealing sensitivity to Gribov copies and aligning with DSE/FRGE solutions.

Contribution

It demonstrates the influence of the lowest eigenvalue of the Faddeev-Popov operator on propagator behavior and compares lattice results with continuum solutions.

Findings

Propagators are sensitive to the lowest eigenvalue of the Faddeev-Popov operator.

Low-momentum propagator behavior varies with Gribov copy selection.

Results agree qualitatively with DSE/FRGE decoupling solutions.

Abstract

We study the gluon and ghost propagators of SU(2) lattice Landau gauge theory and find their low-momentum behavior being sensitive to the lowest non-trivial eigenvalue (\lambda_1) of the Faddeev-Popov operator. If the gauge-fixing favors Gribov copies with small (large) values for \lambda_1 both the ghost dressing function and the gluon propagator get enhanced (suppressed) at low momentum. For larger momenta no dependence on Gribov copies is seen. We compare our lattice data to the corresponding (decoupling) solutions from the DSE/FRGE study of Fischer, Maas and Pawlowski [Annals Phys. 324 (2009) 2408] and find qualitatively good agreement.