Notes on noninvertible quantum symmetries in two dimensions

Abstract

In this note we describe a systematic procedure for computing partition functions of noninvertible Rep ($G$) quantum symmetry actions on two-dimensional nonabelian $G$ orbifolds. We apply this procedure to multiplicity-free examples for several nonabelian groups, and check explicitly in those examples that the partition function of a two-dimensional Rep ($G$)-gauged $G$ orbifold, for nonabelian $G$, matches that of the original theory, as expected on general principles. This fills a minor gap in the literature, making quantum symmetries in two-dimensional nonabelian orbifolds more concrete.