# CMSA Quantum Matter/Quantum Field Theory Seminar: Anomaly of the Electromagnetic Duality of Maxwell Theory

CMSA EVENTS

##### Speaker:

Chang-Tse Hsieh *- IPMU and U Tokyo*

via Zoom Video Conferencing: https://harvard.zoom.us/j/977347126

Every physicist knows that the classical electromagnetism is described by Maxwell's equations and that it is invariant under the electromagnetic duality S: (E, B) → (B, −E). However, the properties of the electromagnetic duality in the quantum theory might not be as well known to physicists in general, and in fact are not very well understood in the literature. This is particularly true when going around a nontrivial path in the spacetime results in a duality transformation. In our recent work, we uncovered a feature of the Maxwell theory and its duality symmetry in such a situation, namely that it has a quantum anomaly. We found that the anomaly of this system in a particular formulation is 56 times that of a Weyl fermion. Our result reproduces, as a special case, the known anomaly of the all-fermion electrodynamics—a version of the Maxwell theory where particles of odd (electric or magnetic) charge are fermions—discovered in the last few years.