On the Faddeev-Popov operator in topological field configurations

The confinement of colored objects in QCD is, even after more than thirty years, still a challenging problem. The progress which has been made in its understanding during the last years has been mainly along two directions, which are at first sight quite different. One is based on topological field configurations, like vortices [1]. The other investigates the properties of Green’s functions [2]. The latter approach is currently most successful in a class of gauges, which includes the Landau and Coulomb gauges. In this context, the (Euclidean) Faddeev-Popov operator (FP)