Reflections of Symmetry: Defects, Anomalies, and Unusual Scattering

Boundaries and defects can change how symmetries act in a physical theory. This seminar introduces symmetry-reflecting defects and defect anomalies, then examines how they constrain long-distance behaviour. Topological arguments are applied to scattering processes whose outgoing states appear to carry unexpected quantum numbers, with examples extending to massive theories.