June 21, 2022

Speaker: Yunqin Zheng (IPMU)

Title: Symmetry TFT for non-invertible duality defects

Abstract: A theory admits a non-invertible duality defect if it has an abelian symmetry G and is invariant under gauging G. This defect can be constructed by gauging G on half of the space with Dirichlet boundary condition imposed at the defect locus. In this talk, we will discuss the properties of such defects from the symmetry TFT point of view. In particular, we discuss (1) the fusion rule of the duality defect, and (2) when this non-invertible duality defect can not be reduced to an invertible defect under topological manipulations (hence is intrinsically non-invertible). We explain these via an example: the duality defect in (1+1)d bosonic QFT with G=Z_N.