Gauge potential singularities and the gluon condensate at finite temperatures

TL;DR

This paper investigates the continuum limit of SU(2) lattice gauge theory at finite temperatures, revealing gauge field singularities linked to center degrees of freedom and their relation to the gluon condensate, which varies with temperature.

Contribution

It identifies gauge field singularities originating from center degrees of freedom and relates the action density of Z_2 links to the gluon condensate at finite temperatures.

Findings

Singularities persist in the continuum limit.

Gluon condensate increases with temperature above deconfinement.

Density of singularities extrapolates to a non-zero continuum value.

Abstract

The continuum limit of SU(2) lattice gauge theory is carefully investigated at zero and at finite temperatures. It is found that the continuum gauge field has singularities originating from center degrees of freedom being discovered in Landau gauge. Our numerical results show that the density of these singularities properly extrapolates to a non-vanishing continuum limit. The action density of the non-trivial Z_2 links is tentatively identified with the gluon condensate. We find for temperatures larger than the deconfinement temperature that the thermal fluctuations of the embedded Z_2 gauge theory result in an increase of the gluon condensate with increasing temperature.