Exotic Branes in Exceptional Field Theory: $E_{7(7)}$ and Beyond

TL;DR

This paper explores exotic branes in string and M-theory using Exceptional Field Theory, revealing their duality properties and unifying known solutions within a single framework, especially for objects with highly non-perturbative tensions.

Contribution

It demonstrates that ExFT provides a natural and consistent framework to describe exotic branes and unifies various solutions in string and M-theory.

Findings

Exotic branes are linked to duality transformations and require ExFT for proper description.

ExFT unifies known solutions in string- and M-theory into a single framework.

Many exotic states lack a consistent supergravity description without ExFT.

Abstract

In recent years, it has been widely argued that the duality transformations of string and M-theory naturally imply the existence of so-called `exotic branes'---low codimension objects with highly non-perturbative tensions, scaling as $g_s^{\alpha}$ for $\alpha \leq -3$. We argue that their intimate link with these duality transformations make them an ideal object of study using the general framework of Double Field Theory (DFT) and Exceptional Field Theory (EFT)---collectively referred to as ExFT. Parallel to the theme of dualities, we also stress that these theories unify known solutions in string- and M-theory into a single solution under ExFT. We argue that not only is there a natural unifying description of the lowest codimension objects, many of these exotic states require this formalism as a consistent supergravity description does not exist.