Scientific Series

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…

Inflation may have occurred at energies up to 10^16 GeV, far beyond the reach of any terrestrial collider. The "cosmological collider" program seeks to extract the mass spectrum and spin content of particles present during inflation from non-Gaussian correlators. Forthcoming large-scale structure…

Higher-curvature gravity can offer UV completions of GR, but generically suffers from 4th-order propagating degrees of freedom often spoiling unitarity, e.g. Stelle gravity. Recently it was noticed that “Einsteinian gravities” allow for higher curvature interactions match Einstein’s spectrum at the…

The Generalized Quantum Stein's Lemma is a theorem in quantum hypothesis testing that provides an operational meaning to the relative entropy within the context of quantum resource theories. Its original proof was found to have a gap, which led to a search for a corrected proof. We formalize the…

I will revisit matrix string theory as a possibly non-perturbative formulation of the superstring S-matrix, and discuss its implications and tests

We derive a cutting rule for equal-time in-in correlators, including cosmological correlators based on Keldysh r/a basis, which decomposes diagrams into fully retarded functions and cut-propagators consisting of Wightman functions. Our derivation relies only on basic assumptions such as unitarity…