Scientific Series

Gibbons and Hawking proposed that the Euclidean gravity path integral with periodic boundary conditions in time computes the thermal partition sum of gravity. As a corollary, they argued that a derivative of the associated free energy with respect to the Euclidean time period computes gravitational…

Cosmological correlation functions probe the origins of structure in the universe. We view them as a prototype for time-dependent correlators and finite-temperature correlators in QFT. I will share recent work on the simple discrete geometries and spacetime pictures that control these correlators at…

Tidal disruption events — where an unfortunate star is destroyed by a previously quiescent supermassive black hole — offer a unique probe of the low mass end of the supermassive black hole population. Recent observational advances have lead to the discovery of ~100 such events, many of which are…

Defects and boundaries play an important role in a wide range of physical contexts, from particle physics to critical phenomena. In this talk, I will discuss how bulk symmetries can be realized in subtle ways in the presence of such impurities, introducing the concepts of symmetry reflecting defects…

I will describe new ideas relating quantum chaos to the complexity of time evolution. One approach treats physical time evolution as a quantum computation, and bounds the smallest quantum circuit that can simulate this evolution. The second approach quantifies how ergodically and rapidly a quantum…

Interacting fermions exhibit a rich landscape of surface defects. We investigate novel surface critical phenomena in systems governed by the three-dimensional Gross–Neveu–Yukawa CFT. In particular, we obtain exact infrared solutions for a class of defect renormalization group flows and demonstrate…

Identifying which boundary conditions preserve integrability in two-dimensional sigma-models is a basic structural question, relevant from open string dynamics to impurity problems. I will discuss a simple analytic approach that determines integrable boundary conditions through the divisor structure…

Suppose our universe really had a huge cosmological constant. What would this mean observationally? For a homogeneous universe the answer is clear, but if the universe is inhomogeneous at the Planck scale the question becomes more subtle. At the level of initial data, $\Lambda$ can be "hidden" in…

The detection of gravitational waves from binary black hole mergers enables us to observe the behavior of spacetimes in the strong-field, highly dynamical regime. The LIGO–Virgo–KAGRA collaboration has now observed hundreds of such events, offering several exciting candidates with differing…

Modern quantum experiments achieve coherences and scales once only dreamed of, pushing the limits of physics and computation. To understand and guide these advances, the questions we ask of quantum physics today---centered around the behavior of quantum information and complexity in large coherent…