HET Journal Club: James Ratcliffe

Speaker:  James Ratcliffe,  University of Southhampton 

Title: 2d or not 2d: N = 2 SYM, localization, and chiral algebras

Abstract: Supersymmetric localization can be used to obtain an explicit form of certain quantum observables. However, their analytic behaviour as a function of a theory’s parameters can be obscured by a finite-dimensional, but complicated, integral. In this talk I will discuss the analytic continuation of the partition function of N = 2 SYM with massless matter, as a function of the coupling constant. I will show that the localized expression can be computed as a sum of its residues, only when the theory is superconformal, and only for complex values of the coupling constant. Motivated by resurgence results, I will argue that this expression contains rich non-perturbative data and provide an interpretation in terms of 4d Higgs branch localization. I will further show that this expression can be reproduced by a well-motivated 2d theory based on the "A/2-twisted" model and the chiral algebra subsector of the 4d SCFT, using SUSY localization.