Double field theory (DFT) is a proposal to incorporate T-duality, a distinctive symmetry of
string theory, as a symmetry of a field theory defined on a double configuration space. The …

We review recent developments in duality symmetric string theory. We begin with the world-
sheet doubled formalism which describes strings in an extended spacetime with extra …

A bstract We construct the first example of a superstratum: a class of smooth horizonless
supergravity solutions that are parameterized by arbitrary continuous functions of (at least) …

A bstract We consider a flux formulation of Double Field Theory in which fluxes are
dynamical and field-dependent. Gauge consistency imposes a set of quadratic constraints …

This review provides an introduction to non-geometric backgrounds in string theory. Starting
from a discussion of T-duality, geometric and non-geometric torus-fibrations are reviewed …

This is a review of exceptional field theory: a generalisation of Kaluza–Klein theory that
unifies the metric and p-form gauge field degrees of freedom of supergravity into a …

A bstract We use a geometric approach to construct a flux formulation for the SL (5) U-duality
manifest exceptional field theory. The resulting formalism is well-suited for studying gauged …

A bstract We present a ten-dimensional theory, named β-supergravity, that contains non-
geometric fluxes and could uplift some four-dimensional gauged supergravities. Building on …

We give a survey of the present status of the microstate geometries called superstrata.
Superstrata are smooth, horizonless solutions of six-dimensional supergravity that represent …

A bstract A new version of double field theory (DFT) is derived for the exactly solvable
background of an in general left-right asymmetric WZW model in the large level limit. This …