In this talk, we introduce the concept of non−invertible selection rules and discuss its consequences. We postulating that the in-states and out-states are charged under a fusion algebra that cannot be described by any group laws. We show that such a selection rule would give new types of constraints for general tree diagrams, but such constraints will reduce to group−like constraints for n-loop diagrams with sufficiently large n. In string theory setup, such a non−invertible selection rule arise from string worldsheet, which reproduces known constarints for scattering on ADE orbifolds. In field theory setups, non−invertible selection rules allow for a general procedure to perform spurion analysis, which could track the origin of small coupling constants in terms of tree−level couplings. Based on 2402.00105 and 2508.14970.

Biography

Hao Zhang is a postdoctoral scholar at Kavli lPMU since 2023,and he obtained his Ph.D. from University of Pennsylvania during 2018-2023. His research interests are symmetries and anomalies in string theory and strongly−coupled QFTs.

Inviter: Jie-Qiang Wu