String Seminar: Antony Speranza (Perimeter Institute) “Anomalies in gravitational charge algebras of null boundaries and black hole entropy”

Seminar Organizer

Event Details

I will discuss how the central charges appearing in near-horizon symmetry algebras arise from an anomalous transformation of the null boundary term in the gravitational action.  This parallels the way in which the holographic Weyl anomaly appears in AdS/CFT, with the ambiguity in the normalization of the null generator being the analogue of the choice of Weyl frame.  As an application, I will analyze a generalization of the near-horizon Virasoro symmetries of Haco, Hawking, Perry, and Strominger, and give a systematic derivation of the Wald-Zoupas fluxes and central charges.  In particular, I will discuss a way to define the quasilocal charges unambiguously, and show that the central charge computed by the charge algebra is directly related to the horizon entropy via the Cardy formula.  
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