The extremal black hole thresholdConfirmed

by Ryan Unger (Stanford University)

Thursday Apr 3, 2025, 1:00 p.m. → 2:30 p.m. America/Toronto

PI/4-400 - Space Room (Perimeter Institute for Theoretical Physics)

In this talk, I will present a proof that extremal Reissner-Nordström arises on the black hole formation threshold for the Einstein equations coupled to a self-gravitating plasma. This constitutes the first rigorous result on critical collapse. I will then discuss a formulation of the stability problem for extremal black holes, and present a positive resolution in the case of extremal Reissner-Nordström perturbed by a self-gravitating neutral scalar field in spherical symmetry, despite the presence of the celebrated Aretakis instability. This is based on joint work with Yannis Angelopoulos (Caltech) and Christoph Kehle (MIT) (2402.10190, 2410.16234).