Singular gauge potentials and the gluon condensate at zero temperature

Abstract

We consider a new cooling procedure which separates gluon degrees of freedom from singular center vortices in SU (2) LGT in a gauge invariant way. Restricted by a cooling scale κ 4 /σ 2 fixing the residual SO(3) gluonic action relative to the string tension, the procedure is RG invariant. In the limit κ → 0 a pure Z(2) vortex texture is left. This minimal vortex content does not contribute to the string tension. It reproduces, however, the lowest glueball states. With an action density scaling like a 4 with β, it defines a finite contribution to the action density at T = 0 in the continuum limit. We propose to interpret this a mass dimension 4 condensate related to the gluon condensate. Similarly, this vortex texture is revealed in the Landau gauge.

Propagators and running coupling from SU(2) lattice gauge theory

“…We point out, however, that it is useful to disentangle the information carried by center elements and coset fields, defined above, when the vacuum energy is investigated. In particular, it was found that -in the continuum limit -the center elements provide a contribution to the gluon condensate [48,49].…”