Abstract: A large class of two-dimensional dilaton-gravity theories in asymptotically AdS2 spacetimes are holographically dual to a matrix integral, interpreted as an ensemble average over Hamiltonians. Viewing these theories as Jackiw-Teitelboim gravity with a gas of defects, I will show how to extend this duality to a broader class of dilaton potentials compared to previous work by including conical defects … Read More

Abstract: Standard lore holds that a consistent theory of quantum gravity cannot have exact global symmetries. In this talk, we will show how simple generalizations of this lore can be used to motivate a number of other well-supported “Swampland conjectures,” thereby highlighting the importance of global symmetries for understanding universal features of quantum gravity.

Abstract:We discuss the role of wormholes and eigenbranes in reconciling geometry with quantum mechanics, working within two dimensional dilaton gravity. First, we review how wormholes enable geometry to accurate capture averaged properties of late time correlators of chaotic quantum systems. Because these are averaged properties, naively, wormholes in gravitational theories suggest some ensemble interpretation of those gravitational theories, here embodied … Read More

Abstract:We show that the presence of replica wormholes in the Euclidean path integral of gravity leads to a non-perturbative violation of any global symmetry present in the low-energy description of quantum gravity. Explicitly, we compute the scattering probability between different charged states in several low-dimensional models of quantum gravity and find a non-vanishing answer. This suggests that the set of … Read More

Abstract: The talk will focus on the spectrum of near-extremal black holes in gravity and near-BPS black holes in supergravity. For concreteness, we will study cases in asymptotically four-dimensional flat space and three-dimensional Anti-de Sitter. This will be done by analyzing quantum effects near the horizon captured by an emergent Jackiw-Teitelboim mode at low temperatures. This will allow us to … Read More

Abstract: Pseudo-entropy is an interesting quantity with a simple gravity dual, which generalizes entanglement entropy such that it depends on both an initial and a final state. In this talk we start with an introduction of this new quantity explaining its basic properties. Next we will study its gravity dual. Finally, we will present recent numerical results of this quantity … Read More

Black hole interiors share some features with cosmology: both have time dependence, singularities, horizons, and very large entropy density. In this talk I will discuss whether recent progress on understanding the black hole interior and the Page curve, based on quantum extremal islands, gives new insight into quantum cosmology.

Topology changing processes have played a central role in recent developments in quantum gravity, and have been argued to lead to an abelian algebra of superselected observables. I will discuss one-dimensional theories of quantum gravity in this context. This invites comparison with a worldline formalism of QFT, with its non-abelian algebra of quantum fields. This apparent tension is resolved by … Read More

ABSTRACT: I will show that the notion of quantum entanglement is notdefined for gravitationally anomalous two-dimensional theories,because they do not admit a local tensor factorization of the Hilbertspace into local Hilbert spaces. Qualitatively, the modular flowcannot act consistently and unitarily in a finite region, if there aredifferent numbers of states with a given energy traveling in the twoopposite directions. I … Read More