Testing spacetime geometry with images of supermassive compact objects: Current status and the future

Virtual

https://youtu.be/ParxdL5gREI General Relativity Seminar Speaker: Prashant Kocherlakota (BHI) Title: Testing spacetime geometry with images of supermassive compact objects: Current status and the future Abstract: Astrophysical black holes (BHs) are expected to be described by the Kerr solution of the Einstein equations. Several frameworks have recently been developed to parametrically deform the Kerr metric in significantly […]

Near extremal de Sitter black holes and JT gravity

Virtual

https://youtu.be/0gWCm0wmgOY General Relativity Seminar Speaker: Chiara Toldo (Harvard) Title: Near extremal de Sitter black holes and JT gravity Abstract: In this talk I will explore the thermodynamic response near extremality of charged black holes in four-dimensional Einstein-Maxwell theory with a positive cosmological constant. The latter exhibit three different extremal limits, dubbed cold, Nariai and ultracold configurations, with […]

Quasinormal modes and Ruelle resonances: mathematician’s perspective

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/FyJ6TieNQBc General Relativity Seminar Speaker: Maciej Zworski, UC Berkeley Title: Quasinormal modes and Ruelle resonances: mathematician's perspective Abstract: Quasinormal modes of gravitational waves and Ruelle resonances in hyperbolic classical dynamics share many general properties and can be considered "scattering resonances": they appear in expansions of correlations, as poles of Green functions and are associated to […]

Quasinormal Modes from Penrose Limits

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/taeAnXApzg4 General Relativity Seminar Speaker: Kwinten Fransen (UC Santa Barbara) Title: Quasinormal Modes from Penrose Limits Abstract: In this talk, I will explain how to describe quasinormal modes with large real frequencies using Penrose limits. To do so, I first recall relevant aspects of the Penrose limit, and its resulting plane wave spacetimes, as well as quasinormal […]

Formation of trapped surfaces in the Einstein-Yang-Mills system

Virtual

https://youtu.be/z7q0LGNVPII General Relativity Seminar Speaker: Nikolaos Athanasiou (University of Crete, Greece) Title: Formation of trapped surfaces in the Einstein-Yang-Mills system Abstract: The purpose of this talk is to give an overview of a semi-global existence result and a trapped surface formation results in the context of the Einstein-Yang-Mills system. Adopting a “signature for decay rates” […]

Pseudospectrum and black hole quasinormal mode instability: An ultraviolet universality conjecture

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/teqIIXRJXd4 General Relativity Seminar Speaker: Jose Luis Jaramillo (Bourgogne U.) Title: Pseudospectrum and black hole quasinormal mode instability: an ultraviolet universality conjecture Abstract: Can we measure the ‘effective regularity’ of spacetime from the perturbation of quasi-normal mode (QNM) overtones? Black hole (BH) QNMs encode the resonant response of black holes under linear perturbations, their associated […]

New Phases of N=4 SYM

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/Kt7n_0t6sgo General Relativity Seminar Speaker: Prahar Mitra (University of Cambridge) Title: New Phases of N=4 SYM Abstract: We construct new static solutions to gauged supergravity that, via the AdS/CFT correspondence, are dual to thermal phases in N=4 SYM at finite chemical potential. These solutions dominate the micro-canonical ensemble and are required to ultimately reproduce the microscopic entropy of AdS […]

Gravitational perturbations near to extreme Kerr

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/VdfmeuDoofY General Relativity Seminar Speaker: Alejandra Castro (University of Cambridge) Title: Gravitational perturbations near to extreme Kerr Abstract: Gravitational perturbations of a black hole illustrate the invaluable synergy between theory, experiment, and numerical simulations in general relativity. A recent development in the theory side has been the identification of the relevant degrees of freedom describing the low energy […]

Rough solutions of the relativistic Euler equations

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/8QfTA8wmChY General Relativity Seminar Speaker: Sifan Yu, Vanderbilt University Title: Rough solutions of the relativistic Euler equations Abstract: I will discuss recent works on the relativistic Euler equations with dynamic vorticity and entropy. We use a new formulation of the equations, which has geo-analytic structures. In this geometric formulation, we decompose the flow into geometric "sound-wave […]

Resolving the photon ring

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/KCo0iWFox1s General Relativity Seminar Speaker: Shahar Hadar (University of Haifa) Title: Resolving the photon ring Abstract: In the past few years, the Event Horizon Telescope has released the first close-up interferometric images of two supermassive black holes, M87* and SgrA*. It is believed that within these images is embedded a fine, yet-unresolved brightness enhancement called the photon ring. […]

Recent advances in scalar curvature and positive mass theorems

CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

https://youtu.be/kGpZ0nRcZRU General Relativity Seminar Speaker: Tin Yau Tsang, University of California Irvine Title: Recent advances in scalar curvature and positive mass theorems Abstract:  First, we have a review of classical tools for studying scalar curvature and positive mass theorem. Then we are going to discuss some advances and new perspectives on these tools which lead […]

The localized seed-to-solution method for the Einstein constraints

Virtual

https://youtu.be/eGU1AQBcxNw General Relativity Seminar Speaker: Philippe G. LeFloch, Sorbonne University and CNRS Title: The localized seed-to-solution method for the Einstein constraints Abstract: I will discuss advances on asymptotically Euclidian initial data sets and the variational method introduced by J. Corvino and R. Schoen. This talk is based on joint papers with The-Cang Nguyen (Montpellier) and Bruno […]