Flux tube formation and the Weingarten representation of center vortices and chains

Abstract: We review some recent results regarding the formulation of mixed ensembles of oriented and nonoriented center vortices based on the Weingarten representation for the sum over surfaces. This framework enabled a partition function for the Abelian-projected ensemble of vortex worldsurfaces, previously formulated as a wavefunctional peaked at center-vortex loops. In particular, we showed how an Abelian ensemble can account for $N$-ality while supporting a ``dual superconductor'' model for confinement. This formulation also clarified the description of the Goldstone modes for percolating surfaces with non-Abelian degrees of freedom, used in the original mechanism for the formation of a confining flux tube due to the percolating mixed ensemble.