Evidence for the reality of singular configurations in SU(2) gauge   theory
  We consider the SU(2) lattice gauge model and investigate numerically the continuum limit of the simple center vortices which are singular configurations of the gauge fields. We found that the vortices remain alive in the continuum theory. Also we investigate the Creutz ratio and found that for all $\beta$ it vanishes for those field configurations which do not contain the simple center vortices inside the considered Wilson loop. It leads us to the conclusion that these singular field configurations play a real role in the continuum theory. 
B.L.G. Bakker, A.I. Veselov, and M.A. Zubkov