April 19, 2022

Speaker: Du Pei (Harvard)

Title: On Symmetries of 2d TQFTs and the Equivariant Verlinde Formula

Abstract: In this talk, we will discuss (generalized) symmetries of 2d semisimple TQFTs. We will show that, in a special basis, the 0-form symmetries always act as permutations while 1-form symmetries act by phases. This leads to an explicit description of the gauging of these symmetries. These results can be used to better understand compactifications of 6d (2,0) theories. In particular, we will use it to generalize the equivariant Verlinde formula to the case of general Lie groups, which leads to many predictions for the geometry of Hitchin moduli spaces.