Time: 10:30-12:00  (Beijing time) Wednesday, 2025/11/26 (November 26)

Location: Room 401, Building 7, UCAS Zhongguancun Campus

Speaker: Ran Luo 罗然, Peking University



Abstract:

Generalized global symmetries have played a central role in theoretical physics for over a decade. By representing internal symmetries as topological operators, higher category theory provides a powerful language for describing symmetry actions, gauging, and the classification of gapped phases. However, most existing categorical frameworks rely on fusion categories, which require finite semisimplicity and therefore exclude continuous Lie group symmetries.

In this talk, I will present a categorical framework that incorporates Lie group symmetries into the SymTFT program. Focusing first on the U(1) case, I will show how the categorical structures familiar from discrete symmetries extend naturally to Lie groups by using skyscraper sheaves on the group manifold. I will explain how this framework allows one to compute the modular data of the SymTFT and analyze its possible boundary conditions. I will then discuss the issue of finiteness and motivate the introduction of quasi-coherent sheaves to address it. I will conclude with remarks on applications and possible generalizations.

This talk is based on [arXiv:2509.13170].


Bio: Ran Luo is a PhD candidate at School of Physics, Peking University. His research focuses on generalized symmetries across high-energy physics, field theory and condensed matter physics.

Link for Zoom meeting:

https://us06web.zoom.us/j/85715129440?pwd=QlJJRFBWWFRLMkxCVmcxZ1RKdlRxQT09

Meeting ID: 857 1512 9440
Passcode: 501105