GP seminar: Non-invertible Symmetries of 2d Non-Linear Sigma Models

Abstract: Global symmetries can be generalised to transformations generated by topological operators, including cases in which this operator does not have an inverse. A family of such topological operators are related to dualities via the procedure of half-space gauging. I will discuss the construction of non-invertible defects based on T-duality in two dimensions, generalising the well-known case of the free compact boson to any Non-Linear Sigma Model with Wess-Zumino term which is T-dualisable. I will discuss how these symmetries can be used to constrain renormalisation group flows, and their fate in String Theory.

This is a seminar in the Centre of Geometry and Physics seminar series.