Speaker: Zipei Zhang, University of Wisconsin–Madison
Abstract: Symmetry can place exact constraints on a quantum field theory even when its low-energy dynamics are strongly coupled. In this talk, I will introduce generalized symmetries through topological defects and background gauge fields, and explain how ’t Hooft anomalies constrain possible infrared phases. I will illustrate these ideas with the one-form center symmetry of four-dimensional SU(N) Yang–Mills theory and its implications at theta = pi. I will then turn to non-invertible symmetries in two-dimensional adjoint QCD, where topological lines give an argument for deconfinement, and close with a brief look at their applications in more phenomenologically relevant gauge theories.