Landau gauge ghost and gluon propagators in SU(2) lattice gauge theory: Gribov ambiguity revisited

TL;DR

This study revisits the Gribov ambiguity in Landau gauge for SU(2) lattice gauge theory, showing that considering the full symmetry group affects the ghost and gluon propagators, especially at low momenta.

Contribution

It introduces a method that accounts for the full symmetry group, enlarging gauge orbits and fixing the Landau gauge at higher extrema, impacting propagator results.

Findings

Enhanced gauge fixing alters ghost propagator at small momenta

Gluon propagator is also affected by the new gauge fixing method

Results challenge the common belief about Gribov ambiguities' effects

Abstract

We reinvestigate the problem of Gribov ambiguities within the Landau (or Lorentz) gauge for the ghost and gluon propagators in pure SU(2) lattice gauge theory. We make use of the full symmetry group of the action taking into account {\it large}, i.e. non-periodic $\mathbb{Z}(2)$ gauge transformations leaving lattice plaquettes invariant. Enlarging in this way the gauge orbits for any given gauge field configuration the Landau gauge can be fixed at higher local extrema of the gauge functional in comparison with standard (overrelaxation) techniques. This has a clearly visible effect not only for the ghost propagator at small momenta but also for the gluon propagator, in contrast to the common belief.