N=2 S-duality via Outer-automorphism Twists

TL;DR

This paper explores how introducing outer-automorphism twists via branch cuts on Riemann surfaces enhances the understanding of S-dualities in 4d N=2 theories derived from 6d N=(2,0) theories, reproducing known dual pairs.

Contribution

It demonstrates a method to generate additional S-dualities by incorporating outer-automorphism twists, extending previous approaches to 4d N=2 theories.

Findings

Reproduces known S-dual pairs using new twist techniques

Shows how branch cuts induce transformations related to Dynkin diagram symmetries

Extends the framework for understanding dualities in 4d theories

Abstract

Compactification of 6d N=(2,0) theory of type G on a punctured Riemann surface has been effectively used to understand S-dualities of 4d N=2 theories. We can further introduce branch cuts on the Riemann surface across which the worldvolume fields are transformed by the discrete symmetries associated to those of the Dynkin diagram of type G. This allows us to generate more S-dualities, and in particular to reproduce a couple of S-dual pairs found previously by Argyres and Wittig.