Carrollian physics at the black hole horizon Article Swipe
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· 2019
· Open Access
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· DOI: https://doi.org/10.1088/1361-6382/ab2fd5
· OA: W2924313363
We show that the geometry of a black hole horizon can be described as a\nCarrollian geometry emerging from an ultra-relativistic limit where the\nnear-horizon radial coordinate plays the role of a virtual velocity of light\ntending to zero. We prove that the laws governing the dynamics of a black hole\nhorizon, the null Raychaudhuri and Damour equations, are Carrollian\nconservation laws obtained by taking the ultra-relativistic limit of the\nconservation of an energy-momentum tensor; we also discuss their physical\ninterpretation. We show that the vector fields preserving the Carrollian\ngeometry of the horizon, dubbed Carrollian Killing vectors, include BMS-like\nsupertranslations and superrotations and that they have non-trivial associated\nconserved charges on the horizon. In particular, we build a generalization of\nthe angular momentum to the case of non-stationary black holes. Finally, we\ndiscuss the relation of these conserved quantities to the infinite tower of\ncharges of the covariant phase space formalism.\n
