Event Category: String Seminar

S-folds are analogues of manifolds where transition functions are not just coordinate changes, as in any theory of gravity, but also involve elements of the S-duality group. Peculiar solutions like this have been the subject of intense speculation in the past few years, but it is usually hard to establish their existence, because the string coupling necessarily becomes strong in … Read More

Abstract: There exists a rich set of relations between entanglement entropies of a multi-partite quantum system, some applying universally to all quantum systems (such as strong sub-additivity), some pertaining to some limited but interesting subclass of systems (such as monogamy of mutual information in holography). We focus on QFTs with a holographic dual describing a classical geometry in the bulk, … Read More

We construct a nearly-AdS2 solution describing an eternal traversable wormhole. The solution contains negative null energy generated by quantum fields under the influence of an external coupling between the two boundaries. In parallel, we discuss two SYK systems coupled by a relevant interaction. The physics of the two cases is very similar. They both share a “gravitational” subsector which is … Read More

Abstract: We discuss a long traversable wormhole solution in four dimensions. Such solutions are forbidden in the classical theory, but allowed in the quantum case. It is “long” because it takes longer to go through the wormhole than through the ambient space, so it is consistent with causality. It is an illustration of a solution where spacetime has a non-trivial … Read More

Abstract: We consider the emergence from quantum entanglement of spacetime geometry in a bulk region. For certain classes of quantum states in an appropriately factorized Hilbert space, a spatial geometry can be defined by associating areas along codimension-one surfaces with the entanglement entropy between either side. We show how Radon transforms can be used to convert this data into a … Read More

Black holes are quantum chaotic systems and so we expect their energy levels to be described by random matrix statistics. In this talk we discuss our progress in explaining these statistical properties using nonperturbative phenomena in quantum gravity.