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Open AccessArticle

Entropy Budget for Hawking Evaporation

Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University, 18000 Prague, Czech Republic
Instituto de Física Fundamental (IFF-CSIC), Serrano 121, 28006 Madrid, Spain
School of Mathematics and Statistics, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand
Author to whom correspondence should be addressed.
Universe 2017, 3(3), 58;
Received: 30 January 2017 / Revised: 17 July 2017 / Accepted: 18 July 2017 / Published: 22 July 2017
(This article belongs to the Special Issue Varying Constants and Fundamental Cosmology)
Blackbody radiation, emitted from a furnace and described by a Planck spectrum, contains (on average) an entropy of 3 . 9 ± 2 . 5 bits per photon. Since normal physical burning is a unitary process, this amount of entropy is compensated by the same amount of “hidden information” in correlations between the photons. The importance of this result lies in the posterior extension of this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget for the evaporation process. In order to carry out this calculation, we adopt a variant of the “average subsystem” approach, but consider a tripartite pure system that includes the influence of the rest of the universe, and which allows “young” black holes to still have a non-zero entropy; which we identify with the standard Bekenstein entropy. View Full-Text
Keywords: black holes; unitarity; information; entropy; entanglement; Clausius entropy; Bekenstein entropy; coarse-grained entropy black holes; unitarity; information; entropy; entanglement; Clausius entropy; Bekenstein entropy; coarse-grained entropy
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MDPI and ACS Style

Alonso-Serrano, A.; Visser, M. Entropy Budget for Hawking Evaporation. Universe 2017, 3, 58.

AMA Style

Alonso-Serrano A, Visser M. Entropy Budget for Hawking Evaporation. Universe. 2017; 3(3):58.

Chicago/Turabian Style

Alonso-Serrano, Ana; Visser, Matt. 2017. "Entropy Budget for Hawking Evaporation" Universe 3, no. 3: 58.

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