Gauged 2-form Symmetries in 6D SCFTs Coupled to Gravity

TL;DR

This paper investigates how discrete 2-form symmetries in 6D superconformal field theories are affected when coupled to gravity, revealing conditions under which these symmetries are gauged, with implications for string theory and F-Theory models.

Contribution

It demonstrates that non-primitively embedded charge lattices lead to gauged 2-form symmetries in 6D supergravity, providing a geometric understanding and concrete examples within string theory frameworks.

Findings

Gauged 2-form symmetries occur when charge lattices are non-primitively embedded.

The embedding of charge lattices determines the gauging of 2-form symmetries.

Results are consistent with dual 5D reductions and string theory constructions.

Abstract

We study six dimensional supergravity theories with superconformal sectors (SCFTs). Instances of such theories can be engineered using type IIB strings, or more generally F-Theory, which translates field theoretic constraints to geometry. Specifically, we study the fate of the discrete 2-form global symmetries of the SCFT sectors. For both $(2,0)$ and $(1,0)$ theories we show that whenever the charge lattice of the SCFT sectors is non-primitively embedded into the charge lattice of the supergravity theory, there is a subgroup of these 2-form symmetries that remains unbroken by BPS strings. By the absence of global symmetries in quantum gravity, this subgroup much be gauged. Using the embedding of the charge lattices also allows us to determine how the gauged 2-form symmetry embeds into the 2-form global symmetries of the SCFT sectors, and we present several concrete examples, as well as some general observations. As an alternative derivation, we recover our results for a large class of models from a dual perspective upon reduction to five dimensions.