False vacua are commonplace in quantum field theory, where general arguments suggest that any given system will end up in the true vacuum provided one waits long enough. We consider examples of extremely long-lived false vacua in quantum field theory. The false vacua in question are protected by a discrete (d-1)-form symmetry, where d is the spacetime dimension. The lifetimes of false vacua are set by the tension of branes charged under a higher-form gauge symmetry. We focus our discussion on abelian gauge theories in two dimensions and QCD. In both cases the higher-form symmetries can be viewed as arising from a modified sum over topological sectors.
Host: Erich Poppitz