PGI Seminar Spring | "A Few Extremal Surprises"

Date
Feb 3, 2025, 12:30 pm1:30 pm
Location
Jadwin Hall - 4th Floor PGI

Speaker

Details

Event Description

Abstract:

I will review a series of results regarding the extremal limit of generic black holes in both Einstein and Einstein-Maxwell theory. We will see that in AdS, at low temperatures, large tidal forces arise at the horizon. These tidal forces lead to a weak null singularity in the extremal limit. The singularities persist in higher dimensions and become even more serious. In particular, the Kretschmann scalar generically blows up at the horizon.

Asymptotically flat black holes in four dimensions are free of these pathologies. However, introducing higher-curvature corrections (expected, for instance, from QED) renders the extremal horizon singular. Although the non-extremal geometry remains smooth, it is significantly altered at small temperatures. This effect becomes surprisingly large, even for black holes below Thorne's limit, leading to deviations of a few percent from the classical solution.