MS Seminar (Mathematics - String Theory)

Speaker: Lakshya Bhardwaj (Perimeter Institute for Theoretical Physics)
Title: State-sum constructions of spin-TFTs and fermionic SPT phases
Date: Tue, Aug 23, 2016, 13:15 - 14:30
Place: Seminar Room A
Abstract: An interesting property of 2+1d TFTs is that they can be constructed from the data of any one of their topological boundary conditions. In this talk, we will obtain a physical understanding of this construction. We will also extend the co nstruction to engineer TFTs with non-trivial 0-form or 1-form global symmetries. As we will see, a spin-TFT can then be described using the data of an ordinary TFT with an anomalous 1-form symmetry. We can then concretely identify fermionic SPT phases as a sub-class of spin-TFTs. It is also possible to determine the group structure of fermionic SPT phases using this for malism and here the quaternions make a surprise appearance!