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Open AccessGeneralised U-dual solutions via ISO(7) gauged supergravity
We study a solution generating technique in supergravity which can be viewed as a generalised version of U-duality, taking solutions of type IIA supergravity on a 6-sphere with RR flux to new solutions of 11-d...
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Open AccessNon-isometric U-dualities
I study generalisations of U-duality transformations which do not rely on the existence of isometries. I start by providing more details of a recently proposed generalised U-duality map between solutions of ty...
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Article
Open AccessDoubled space and extended supersymmetry
The doubled formulation of the worldsheet provides a description of string theory in which T-duality is promoted to a manifest symmetry. Here we extend this approach to
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Open AccessGeneralised U-dual solutions in supergravity
We discuss the notion of generalised U-duality as a solution generating technique in supergravity. We demonstrate a method to take solutions of type IIA supergravity on a 3-sphere, with NSNS flux, to new solut...
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Article
Open AccessA non-relativistic limit of M-theory and 11-dimensional membrane Newton-Cartan geometry
We consider a non-relativistic limit of the bosonic sector of eleven-dimensional supergravity, leading to a theory based on a covariant ‘membrane Newton-Cartan’ (MNC) geometry. The local tangent space is split...
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Open AccessNon-Riemannian isometries from double field theory
We explore the notion of isometries in non-Riemannian geometries. Such geometries include and generalise the backgrounds of non-relativistic string theory, and they can be naturally described using the formali...
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Article
Open AccessExploring exceptional Drinfeld geometries
We explore geometries that give rise to a novel algebraic structure, the Exceptional Drinfeld Algebra, which has recently been proposed as an approach to study generalised U-dualities, similar to the non-Abeli...
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Article
Open AccessNon-relativistic duality and \( T\overline{T} \) deformations
We make some observations connecting non-relativistic limits of string theory with T ...
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Article
Open AccessA worldsheet supersymmetric Newton-Cartan string
We construct a (locally) supersymmetric worldsheet action for a string in a non-relativistic Newton-Cartan background. We do this using a doubled string action, which describes the target space geometry in an O(D...
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Open AccessNon-Riemannian geometry of M-theory
We construct a background for M-theory that is moduli free. This background is then shown to be related to a topological phase of the E8(8) exceptional field theory (ExFT). The key ingredient in the construction ...
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Article
Open AccessOpen exceptional strings and D-branes
We study D-branes in the extended geometry appearing in exceptional field theory (or exceptional generalised geometry). Starting from the exceptional sigma model (an Ed(d) covariant worldsheet action with extra t...
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Article
Open AccessO-folds. Orientifolds and orbifolds in exceptional field theory
We describe conventional orientifold and orbifold quotients of string and M-theory in a unified approach based on exceptional field theory (ExFT). Using an extended spacetime, ExFT combines all the maximal ten...
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Article
Open AccessThe exceptional sigma model
We detail the construction of the exceptional sigma model, which describes a string propagating in the “extended spacetime” of exceptional field theory. This is to U-duality as the doubled sigma model is to T-dua...
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Article
Open AccessFive-brane actions in double field theory
We construct an action for NSNS 5-branes which is manifestly covariant under O(d, d). This is done by doubling d of the spacetime coordinates which appear in the worldvolume action. By formulating the DBI part of...
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Article
Open AccessParticle actions and brane tensions from double and exceptional geometry
Massless particles in n + 1 dimensions lead to massive particles in n dimensions on Kaluza-Klein reduction. In string theory, wrapped branes lead to multiplets of massive particles in n dimensions, in representat...
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Open AccessDoubled strings, negative strings and null waves
We revisit the fundamental string (F1) solution in the doubled formalism. We show that the wave-like solution of double field theory (DFT) corresponding to the F1/pp-wave duality pair is more properly a soluti...
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Open AccessConserved currents of double field theory
We find the conserved current associated to invariance under generalised diffeomorphisms in double field theory. This can be used to define a generalised Komar integral. We comment on its applications to solut...
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Open AccessNon-commutativity and non-associativity of the doubled string in non-geometric backgrounds
We use a T-duality invariant action to investigate the behaviour of a string in non-geometric backgrounds, where there is a non-trivial global O(D, D) patching or monodromy. This action leads to a set of Dirac br...
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Open AccessGeometry and fluxes of SL(5) exceptional field theory
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 supergravities with geometric a...
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Article
Open AccessM-theory and type IIB from a duality manifest action
We revisit the SL(5) U-duality manifest action constructed by Berman and Perry in an extended spacetime. Upon choosing a four-dimensional solution to the section condition constraint, the theory reduces to a f...
