Falk Hassler
A geometric perspective on duality symmetries in supergravity
Symmetries are one of the major tools to understand the structure of physical theories. But even the most powerful symmetry is useless if it is hidden and therefore not accessible in calculations. Prominent examples are S-, T- and U-dualities of superstrings and branes. We know that they unify the five perturbative superstring theories and M-theory into a single framework, but their imprints on the low-energy effective supergravity theories are subtle and easy to miss. A framework which addresses this issue is (exceptional) generalized geometry. Although thought as a natural extension of geometry to an extended tangent bundle, it still lacks fundamental objects of differential geometry like a Riemann tensor. After a short review of the most important differences between generalized and standard differential geometry, I will present the underlying cause for this trouble and present a proposal for a solution which gives a new, geometric perspective on duality symmetries in supergravity. This approach will not just resolve some old puzzles but it also has direct applications, leading to a much broader notion of dualities in supergravity that can be used to generate new solutions using a tool known as consistent truncations.