Documents de présentation
I will present a powerful new method that for the first time allows us to compute the Kaluza-Klein spectrum of a large class of string theory compactifications. This includes geometries with little to no remaining (super-)symmetries, completely inaccessible by standard methods. I will discuss various applications of this method, including to the AdS/CFT correspondence and to the stability of...
I will discuss the large-N limit of the sphere partition function and the topologically twisted index of the ABJM theory and related SCFTs arising from M2-branes. Focusing on the subleading terms in the large-N expansion, I will study the implications of these results for black hole physics and holography.
Recent years have seen remarkable progress in our understanding of black holes: for black holes in AdS coupled to a bath, Page curves consistent with unitarity have been obtained through semi-classical computations involving quantum extremal surfaces. These computations are largely based either on two-dimensional models or on bottom-up braneworld models which may or may not make sense as...
We will review recent constructions of AdS_3 and AdS_2 solutions with 4 supercharges for which the dual two dimensional and one dimensional conformal field theories have been identified as the IR fixed points of quiver-like field theories. These solutions describe the near horizon geometry of extremal black holes, so their dual CFTs can be used to compute their microscopical degrees of...
Recent advances in the scattering amplitude-based approach to the Post-Minkowskian expansion of classical general relativity have demonstrated that this new approach holds the promise of significantly changing the efficiency of computations in general relativity. This approach completes the post-Newtonian computations by providing information beyond its regime of validity. This framework...
The talk will explain the asymptotic structure of gravity in the asymptotically flat case by making central use of the Hamiltonian formalism. In particular, how the infinite-dimensional asymptotic symmetry group (BMS group) emerges at spatial infinity will be discussed. The case of electromagnetism will also be presented and extensions to supergravity will be addressed.
An understanding of generalized global symmetries of a Quantum Field Theory (QFT) can provide deep insight into its strong coupling behavior. For example, spontaneous non-breaking of 1-form symmetry signals confinement. Standard tools for studying generalized global symmetries often rely on the existence of a Lagrangian description, and hence only apply to weakly coupled QFTs. However, all the...
Non-trivial K-theory groups and non-trivial cobordism groups can lead to global symmetries which are conjectured to be absent in quantum gravity. In this talk, a correspondence between the two groups is proposed. It is inspired by open-closed string duality and relies on a mathematical result known as Conner-Floyd isomorphism. As an application, it is shown how to recover known tadpole...
In this talk I will describe recent advances on the study of the Higgs branch of rank-1 and rank-2 4d N=2 SCFTs. In particular, I will describe how one can obtain magnetic quivers for almost all these theories, which in turn allows to describe the Hasse diagram of the Higgs branch and sheds light on the the corresponding chiral ring. We also explore how SCFTs are connected by RG flows.
We study D-instanton contributions to supergravity scattering amplitudes beyond the leading order. These effects are non-perturbative in the string coupling, and are constrained by S-duality at low orders in the momentum expansion of the spacetime effective action. Our worldsheet approach reproduces the results expected from S-duality and also predicts infinitely many terms at higher orders in...
The topological string free energy is given by an asymptotic series in the topological string coupling. I will first discuss how a finite difference equation can be derived from this asymptotic series for a class of Calabi-Yau backgrounds and how analytic solutions of these equations can be found. These solutions provide access to the non-perturbative structure and strong topological string...
Euclidean D-branes wrapped on non-trivial cycles of a Calabi-Yau threefold are known to affect the metric on the hypermultiplet moduli space determining the effective action of type II strings on such manifolds. After reviewing the existing results on the instanton corrected metric following from a combination of constraints imposed by supersymmetry and dualities, I'll show how the D-instanton...
While multicenter black holes in asymptotically flat space have long been object of study, the construction of multi black holes geometries in Anti-de Sitter spacetimes remains so far elusive. In this talk I will discuss recent progress on the search for these solutions. Working in the probe approximation, I will show that there exist stable ad metastable black hole bound states in...
Following the recent work of Eberhardt, Gaberdiel and Gopakumar, exact comparison between various quantities living on the two sides of the AdS/CFT correspondence has become a possibility. The goal of this work is to extend the existing holographic dictionary to include some non-perturbative vacua on both sides. We start by constructing various D-branes of the string theory on ${\rm...
One of the major achievements of the study of integrability in AdS/CFT has been the development of the Quantum Spectral Curve (QSC): a powerful set of equations which give access to the full planar spectrum of N=4 SYM at finite coupling. These equations, which have the form of a nonlinear Riemann-Hilbert problem, are the central mathematical structure of integrability, and recent results...
The eigenstate thermalization hypothesis is one of the most universal features of chaotic quantum many-body systems, which claims that matrix elements of simple operators in high energy states has a universal structure which treats off-diagonal elements statistically. Along with the random-matrix like behaviour of energy eigenstates, it is one of the main smoking guns of quantum chaos. In this...
This talk will start with an introduction to hydrodynamisation in an FRW universe. I first briefly describe the set-up and show how a hydrodynamic plasma dilutes and falls out of equilibrium due to expansion towards empty de Sitter spacetime [1]. Finally, I will show new technical advances that allowed us to dynamically evolve the boundary metric in accordance with the Friedmann equations [2]....
I will discuss recent new examples providing new links between quantum information, holography and quantum gravity: I will first introduce a refinement of the usual entanglement entropy for theories with global conserved charges, the so-called symmetry resolved entanglement entropy, and discuss its recent implementation in AdS3/CFT2 (2012.11274, 2108.09210). I will then elaborate on the use of...
