Phases of theories with ${\mathbb{Z}}_N$ 1-form symmetry and the roles of center vortices and magnetic monopoles

Abstract

We analyze the phases of theories which only have a microscopic ${\mathbb{Z}}_N$ 1-form symmetry, starting with a topological BF theory and deforming it in accordance with microscopic symmetry. These theories have a well-defined notion of confinement. Prototypical examples are pure $SU(N)$ gauge theories and ${\mathbb{Z}}_N$ lattice gauge theories. Our analysis shows that the only generic phases are in $d=2$, only the confined phase; in $d=3$, both the confined phase and the topological BF phase; and in $d=4$, the confined phase, the topological BF phase, and a phase with a massless photon. We construct a ${\mathbb{Z}}_N$ lattice gauge theory with a deformation which, surprisingly, produces up to $(N-1)$ photons. We give an interpretation of these findings in terms of two competing pictures of confinement -- proliferation of monopoles and proliferation of center vortices -- and conclude that the proliferation of center vortices is a necessary but insufficient condition for confinement, while that of monopoles is both necessary and sufficient.

Comments: 11 pages, 3 figures. V2 minor corrections