Physics Seminar
Date: Tuesday, 06 February 2024
Time: 1:45 PM
Venue: Lecture Hall 1
An entropy current and the second law in higher derivative theories of gravity
Prateksh Dhivakar
IIT Kanpur.
06-02-24

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Abstract

We construct a proof of the second law of black hole mechanics in an arbitrary diffeomorphism invariant theory of gravity working within the approximation of linearized dynamical fluctuations around stationary black holes. We achieve this by establishing the existence of an entropy current defined on the horizon of the dynamically perturbed black hole in such theories. By construction, this entropy current has non-negative divergence, suggestive of a mechanism for the dynamical black hole to approach an equilibrium configuration via entropy production as well as the spatial flow of it on the null horizon. This enables us to argue for the second law in its strongest possible form, which has a manifest locality at each space-time point. Finally, we will discuss how one can generalize this construction to non-minimally coupled matter theories and generic Chern-Simons theories. Based on arXiv:2105.06455 [hep-th], arXiv:2206.04538 [hep-th] and arXiv:2306.12491 [hep-th].