Monopole vacuum in non-Abelian theories

It is shown that, in the theory of interacting Yang-Mills fields and a Higgs field, there is a topological degeneracy of Bogomol'nyi-Prasad-Sommerfield (BPS) monopoles and that there arises, in this case, a chromoelectric monopole characterized by a new topological variable that describes transitions between topological states of the monopole in Minkowski space (in just the same way as an instanton describes such transitions in Euclidean space). The limit of an infinitely large mass of the Higgs field at a finite density of the Bogomol'nyi-Prasad-Sommerfield monopole is considered as a model of the stable vacuum in pure Yang-Mills theory. It is shown that, in QCD, such a monopole vacuum may lead to a growing potential, a topological confinement, and an additional mass of the η0 meson. The relationship between the result obtained here for the generating functional of perturbation theory and the Faddeev-Popov integral is discussed.