Speaker: Javier Magan (UPenn)
Title: Generalized symmetries, Noether and Weinberg-Witten.
Abstract: In this talk we describe new theorems concerning the mixing of symmetries in QFT. In particular, we show that generalized symmetries cannot be charged under a continuous global symmetry having a Noether current. The results follow from a finer classification of twist operators, which naturally extends to finite group global symmetries. They unravel topological obstructions to the strong version of Noether’s theorem in QFT, even if under general conditions a global symmetry can be implemented locally by twist operators (weak version). We use these results to rederive Weinberg-Witten’s theorem within local QFT, generalizing it in several directions. We end up discussing the conditions for the strong version to hold, dynamical aspects of QFT’s with non-compact generalized symmetries, scale vs conformal invariance in QFT and connections with the Coleman-Mandula theorem.