A determination of <A^2> and the non-perturbative vacuum energy of Yang-Mills theory in the Landau gauge

TL;DR

This paper investigates the non-perturbative gluon condensate <A^2> and vacuum energy in SU(N) Yang-Mills theory using the 2PPI expansion, revealing a dynamically generated gluon mass.

Contribution

It introduces the use of the 2PPI expansion to analyze the <A^2> condensate and vacuum energy in Yang-Mills theory, providing a non-perturbative approach.

Findings

Identification of a non-zero <A^2> condensate

Evidence for a dynamically generated gluon mass

Calculation of the non-perturbative vacuum energy

Abstract

We discuss the 2-point-particle-irreducible (2PPI) expansion, which sums bubble graphs to all orders, in the context of SU(N) Yang-Mills theory in the Landau gauge. Using the method we investigate the possible existence of a gluon condensate of mass dimension two, <A^2>, and the corresponding non-zero vacuum energy. This condensate gives rise to a dynamically generated mass for the gluon.