Nilpotent orbits and codimension-two defects of 6d N=(2,0) theories

TL;DR

This paper investigates the properties of codimension-2 defects in 6d N=(2,0) theories, characterized by nilpotent orbits, and computes their impact on various physical parameters such as Higgs and Coulomb branches, central charges, and flavor symmetries.

Contribution

It generalizes the understanding of defects in 6d theories by linking nilpotent orbits and outer automorphisms to detailed physical invariants.

Findings

Determines contributions to Higgs and Coulomb branch dimensions.

Calculates central charges a, c, and flavor central charge k.

Provides a framework for classifying defects via nilpotent orbits.

Abstract

We study the local properties of a class of codimension-2 defects of the 6d N=(2,0) theories of type J=A,D,E labeled by nilpotent orbits of a Lie algebra \mathfrak{g}, where \mathfrak{g} is determined by J and the outer-automorphism twist around the defect. This class is a natural generalisation of the defects of the 6d theory of type SU(N) labeled by a Young diagram with N boxes. For any of these defects, we determine its contribution to the dimension of the Higgs branch, to the Coulomb branch operators and their scaling dimensions, to the 4d central charges a and c, and to the flavour central charge k.