The Landau gauge gluon propagator: Gribov problem and finite-size effects

TL;DR

This paper investigates the SU(2) gluon propagator in Landau gauge on the lattice, addressing the Gribov problem and finite-size effects, and finds that improved gauge fixing reduces systematic deviations and reveals a plateau at low momenta.

Contribution

It introduces a gauge fixing method using simulated annealing and Z(2)-flips that improves the gauge functional maxima and reduces finite-size effects in lattice calculations.

Findings

Higher maxima of the gauge functional with the new method.

Finite-size effects become weak for larger lattices.

Gluon propagator shows a plateau at approximately 300 MeV.

Abstract

The SU(2) gluon propagator in Landau gauge is studied on the lattice. Our gauge fixing procedure employs simulated annealing and Z(2)-flips. It finds higher maxima of the gauge functional compared with those obtained with the standard overrelaxation and leads to systematic deviations of the gluon propagator in the infrared region. In particular, finite-size effects for lattice sizes from (1.7 fm)^4 up to (6.5 fm)^4 become weak. The propagator shows a plateau at p \approx 300 MeV.