Physics

I will describe a large ensemble of compactifications of type IIB string theory on Calabi-Yau threefold hypersurfaces, obtained by triangulating polytopes from the Kreuzer-Skarke list. We have developed methods to compute effective theories in the...

Motivated by an apparent counterexample to the Weak Gravity Conjecture, I will describe the difference between black hole extremality bounds and BPS bounds and (relatedly) the difference between superextremal particles and self-repulsive particles...

At the event horizon of a black hole, gravity reaches its most extreme behavior. Studying the dynamics of event horizons is key to understand gravity in the ultra-strong field regime and investigate the most fundamental properties of black holes...

I will discuss the contribution of higher-genus surfaces in JT gravity. In work with Saad and Shenker, we use Mirzakhani's recursion and work of Eynard and Orantin to show that these contributions exactly coincide with the genus expansion of a...

I will review the perturbative (genus) expansion of one-matrix integrals via the loop equations, and the streamlined version due to Eynard. I will review double-scaled matrix integrals and discuss a heuristic method for computing some...

Light scalar dark matter fields can exhibit several interesting aspects to their cosmological evolution. I will focus mostly on structure formation with ultralight axions and with the QCD axion. The standard scenario leads to a suppression of...

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In 1975 Hawking showed that the evaporation of black holes creates a problem for unitarity. This argument can be made rigorous through the small corrections theorem, and implies that there must be a fundamental change in our picture of semiclassical...