Kapustin-Witten Theory and Factorization Homology

I'll introduce you to a family of four-dimensional quantum field theories that were first developed by Kapustin and Witten, who wanted to explain how ideas from physics can be used to study a major problem in representation theory (the geometric Langlands conjecture).  My goal in this talk will be to explain how to start with some physical input, and extract something concrete and mathematical: certain algebras associated to 4-manifolds. 

This is joint work with Owen Gwilliam and Brian Williams.