Equivariant Modular Categories via Dijkgraaf-Witten Theory

Abstract

Based on a weak action of a finite group J on a finite group G, we present a geometric construction of J-equivariant Dijkgraaf-Witten theory as an extended topological field theory. The construction yields an explicitly accessible class of equivariant modular tensor categories. For the action of a group J on a group G, the category is described as the representation category of a J-ribbon algebra that generalizes the Drinfel'd double of the finite group G.

52 pages, 3 figures, v2: typos corrected, v3: conventions concerning left and right actions fixed (mainly section 4)