TITLE: Quasinormal Modes from Penrose Limits ABSTRACT: In this talk, I will explain how to describe quasinormal modes with a large real frequency using Penrose limits. To do so, I first recall relevant aspects of the Penrose limit, as well as the plane wave spacetimes that arise in this limit, to subsequently tie this together with […]
Title: Quantum near extremal black holes and anomalies Abstract: The Bekenstein–Hawking formula gives a coarse-grained count of the number of microstates of a black hole, and it is remarkable that it may sometimes be reproduced from a microscopic count in string theory. However, the standard approach (which we will briefly review) typically relies on supersymmetry by counting […]
Title: Fundamental Physics and Cosmology from Stellar Mass Binary Black Holes Abstract:The first three observing runs of the LIGO, Virgo, and KAGRA gravitational wave detectors produced a wealth of "firsts," including the first observation of multiple "ringdown" modes from a black hole---the remnant of the first-ever binary black hole merger, GW150914. Just like an excited […]
Title: How Much Do We Understand About Early Galaxy Formation? Abstract: The “Cosmic Dawn” of galaxy formation is one of the frontiers of modern astronomy. In the past two years, JWST has provided tantalizing clues about sources in the first several hundred million years of the Universe’s history that challenge our understanding this era, including […]
Title: Universality in a black hole ringing: excitation factors and greybody factors, Abstract: The ringdown gravitational waves emitted by a ringing black hole areimportant for testing strong gravity physics. However, achievingprecise detection requires not only advances in observationaltechniques but also a deeper theoretical understanding of ringdown orquasinormal-mode (QNM) excitation. In this talk, I will explain theuniversality […]
Title: Black holes in space and the "lab": from theory to practice Abstract: This talk focuses on recent theoretical developments in black holes and gravity using techniques from quantum field theory. I will begin by demonstrating how perturbative quantum field theory can be employed to compute the gravitational waveforms generated by astrophysical black holes. Next, I will […]
Title: The Power of Non-invertible Symmetry, Abstract: I will discuss recent advances in a novel class of symmetries in quantum field theories and quantum lattice models, known as non-invertible symmetries. Unlike conventional symmetries governed by Wigner's theorem, these are implemented by conserved operators that have no inverse, challenging and extending the traditional paradigm of symmetry in physics. I […]
Title: From quantum information to black holes and cosmology, Abstract: Black holes have not just become laboratories for astronomers, but also present some of the deepest unsolved problems in theoretical physics. During the past decade surprising connections have been made between ideas from quantum information and gravitational physics. In this talk I will explain several aspects […]
Title: Cauchy-characteristic matching, Abstract: Cauchy-characteristic matching is a novel numerical-relativity technique that enables the evolution of Einstein’s equations on an effectively infinite computational domain. In this talk, I will present our recent successful applications of this method to binary black hole mergers, and demonstrate its transformative potential for modeling tail and memory effects in eccentric binaries.
Title: Where is tree-level string theory? Abstract: Tree-level string theory extends Einstein gravity by an infinite set of massive higher spin particles. From a purely spacetime perspective (if we didn’t know about the worldsheet picture) the consistency of string amplitudes would appear truly miraculous. This prompts the question: is string theory the unique framework for a higher […]
TITLE: Cosmological results from the Dark Energy Spectroscopic Instrument, ABSTRACT: A quarter-century after the discovery of the accelerated expansion of theuniverse, the constraints on dark energy that powers this acceleration havebecome very good, but physical nature of dark energy remains elusive. I willpresent and discuss cosmological results from the measurement of baryonacoustic oscillations (BAO) in […]
Worldline effective theories and gravitational dynamicsWorldline effective theories are incredibly useful tools for studying the dynamics of spatially compact systems, with gravitational binaries being a perfect example. In particular they allow for the import of many tools from quantum field theory, eg. Feynman diagrams, loop integration techniques, dimensional regularization, renormalization group, etc. Work in recent […]