Probing Nonlagrangian Theories via Surface Operators

by Maxime Trepanier (King's College London)

Thursday 30 Mar 2023, 13:30 → 14:30 Europe/Copenhagen

Aud A

There will be a student session at 13:10 before the main talk.

Abstract: Surface operators are string-like defects that appear in many guises in a wide array of QFTs. The most intriguing context in which they arise might be the so-called 6d N=(2,0) superconformal field theories, which are mysterious strongly-coupled theories predicted by string theory with no lagrangian description. In this talk I will explain how surface operators in these theories are analogous to Wilson lines in gauge theories and define a notion of string potential. I will then discuss two powerful nonperturbative approaches to study them: the chiral algebra, which provides an alternative to supersymmetric localization, and the conformal bootstrap. Using these I will extract exact OPE coefficients for protected operators, as well as defect CFT data for nonprotected operators at large N. These methods provide concrete results for the 6d theories and are also applicable more generally, in particular to 4d N=2 theories.

presentation.pdf