Abstract: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 four-dimensional truncation of elevendimensional supergravity. In this paper, we show that the theory contains more than this M-theory reduction. The section condition also admits an SL(5) inequivalent threedimensional solution, upon which the action directly reduces to a three-dimensional truncation of type IIB supergravity. We also discuss the reduction to IIB * supergravity.

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 and non-geometric fluxes. Here we describe all such fluxes for both M-theory and IIB supergravity including the Ramond-Ramond fields for compactifications to seven dimensions. We define the locally non-geometric "R-flux" and globally non-geometric "Q-flux" for M-theory and find a new locally non-geometric R-flux for the IIB theory. We show how these non-geometric fluxes can be understood geometrically and give some examples of how they can be generated by acting with dualities on solutions with geometric or field-strength flux.

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 E 8(8) exceptional field theory (ExFT). The key ingredient in the construction is the embedding of non-Riemannian geometry in ExFT. This allows one to describe non-relativistic geometries, such as Newton-Cartan or Gomis-Ooguri-type limits, using the ExFT framework originally developed to describe maximal supergravity. This generalises previous work by Morand and Park in the context of double field theory.

We construct the 12-dimensional exceptional field theory associated to the group SL(2)× R + . Demanding the closure of the algebra of local symmetries leads to a constraint, known as the section condition, that must be imposed on all fields. This constraint has two inequivalent solutions, one giving rise to 11-dimensional supergravity and the other leading to F-theory. Thus SL(2) × R + exceptional field theory contains both F-theory and M-theory in a single 12-dimensional formalism.