Abstract: The IR Lagrangian of an N=2 supersymmetric gauge theory compactified on R^3 x S^1, around a generic point of its moduli space, is a 3d sigma model with a hyperkahler target space. We consider a related problem of constructing the IR Lagrangian of an N=2 theory on a special family of circle fibrations over R^3 — namely Gibbons-Hawking spaces. … Read More

Abstract: In the context of holographic duality with AdS3 asymptotics, the Ryu-Takayanagi formula states that the entanglement entropy of a subregion is given by the length of a certain bulk geodesic. The entanglement entropy can be operationalized as the entanglement cost necessary to transmit the state of the subregion from one party to another while preserving all correlations with a … Read More

Abstract: I will present recent results on the computation of finite N effects in supergravity in the context of AdS2/CFT1 and AdS4/ABJM holography. I will show how to use localisation to compute all perturbative and nonperturbative charge corrections to the entropy of supersymmetric black holes including complicated number theoretic objects called Kloosterman sums. These are essential to recover an integer … Read More

Abstract: Besides propagating in target space like a point particle, a closed string is also able to wind around non-contractible circles. A direct consequence thereof is T-duality. In the textbook example, it identifies the closed string dynamics on a large and a small circle by interchanging its winding and momentum modes. Patching a background by such dualities clearly goes beyond … Read More

We study various aspects of supergeometry, including obstruction, Atiyah, and super-Atiyah classes. This is applied to the geometry of the moduli space of super Riemann surfaces and to its Deligne-Mumford compactification. For genus greater than or equal to 5, this moduli space is not projected (and in particular it is not split): it cannot be holomorphically projected to its underlying … Read More