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Branches of the Black Hole Wave Function Need Not Contain Firewalls

Bao, Ning and Carroll, Sean M. and Chatwin-Davies, Aidan and Pollack, Jason and Remmen, Grant N. (2018) Branches of the Black Hole Wave Function Need Not Contain Firewalls. Physical Review D, 97 (12). Art. No. 126014. ISSN 2470-0010. doi:10.1103/PhysRevD.97.126014.

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We discuss the branching structure of the quantum-gravitational wave function that describes the evaporation of a black hole. A global wave function which initially describes a classical Schwarzschild geometry is continually decohered into distinct semiclassical branches by the emission of Hawking radiation. The laws of quantum mechanics dictate that the wave function evolves unitarily, but this unitary evolution is only manifest when considering the global description of the wave function; it is not implemented by time evolution on a single semiclassical branch. Conversely, geometric notions like the position or smoothness of a horizon only make sense on the level of individual branches. We consider the implications of this picture for probes of black holes by classical observers in definite geometries, like those involved in the Almheiri-Marolf-Polchinski-Sully construction. We argue that individual branches can describe semiclassical geometries free of firewalls, even as the global wave function evolves unitarily. We show that the pointer states of infalling detectors that are robust under Hamiltonian evolution are distinct from, and incompatible with, those of exterior detectors stationary with respect to the black hole horizon, in the sense that the pointer bases are related to each other via nontrivial transformations that mix the system, apparatus, and environment. This result describes a Hilbert-space version of black hole complementarity.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Bao, Ning0000-0002-3296-1039
Carroll, Sean M.0000-0002-4226-5758
Chatwin-Davies, Aidan0000-0003-1406-9271
Pollack, Jason0000-0003-4754-4905
Remmen, Grant N.0000-0001-6569-8866
Additional Information:© 2018 Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3. Received 20 December 2017; published 20 June 2018. We thank Ahmed Almheiri, Raphael Bousso, William Donnelly, Masahiro Hotta, Cindy Keeler, Yasunori Nomura, Don N. Page, Guillaume Verdon, and Koji Yamaguchi for helpful discussions. This work is supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award No. DE-SC0011632. N. B. is supported by the National Science Foundation, under Grant No. 82248-13067-44-PHPXH. A. C.-D. is supported by a Beatrice and Sai-Wai Fu Graduate Fellowship in Physics and the Gordon and Betty Moore Foundation through Grant No. 776 to the Caltech Moore Center for Theoretical Cosmology and Physics. J. P. is supported in part by the Simons Foundation and in part by the Natural Sciences and Engineering Research Council of Canada. G. N. R. is supported by the Miller Institute for Basic Research in Science at the University of California, Berkeley.
Group:Walter Burke Institute for Theoretical Physics, Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0011632
Beatrice and Sai-Wai Fu Graduate Fellowship, CaltechUNSPECIFIED
Gordon and Betty Moore Foundation776
Simons FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Miller Institute for Basic Research in ScienceUNSPECIFIED
Caltech Moore Center for Theoretical Cosmology and PhysicsUNSPECIFIED
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Issue or Number:12
Record Number:CaltechAUTHORS:20180109-165521863
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84217
Deposited By: Joy Painter
Deposited On:10 Jan 2018 18:00
Last Modified:15 Nov 2021 20:17

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