Abstract
Space-based next-generation interferometers propose to measure the Lyapunov exponents of the nearly bound geodesics that comprise the photon ring surrounding the black hole M87*. We argue that these classical Lyapunov exponents equal the quantum Ruelle resonances describing the late-time approach to thermal equilibrium of the quantum microstate holographically dual to any Kerr black hole such as M87*. Moreover, we identify ‘near-ring regions’ in the phase space of fields propagating on Kerr that exhibit critical behavior, including emergent conformal symmetries. These are analogues for sub-extremal Kerr of the much-studied ‘near-horizon regions’ of (near-)extremal black holes. The emergent conformal symmetries greatly constrain the observational predictions for the fine photon ring substructure around M87* and for quasinormal gravitational-wave ringdowns, as well as any proposal for a quantum holographic dual to the Kerr black hole. More generally, we hope that our identification of several universal features of Kerr spectroscopy provides a useful starting point for a bottom-up approach to holography for astrophysical black holes.
Original language | English |
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Article number | 215001 |
Journal | Classical and Quantum Gravity |
Volume | 39 |
Issue number | 21 |
DOIs | |
State | Published - 3 Nov 2022 |
Bibliographical note
Publisher Copyright:© 2022 IOP Publishing Ltd.
Keywords
- black hole
- holography
- photon ring
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)