Comment on Measurements without probabilities in the final state proposal

Eliahu Cohen, Marcin Nowakowski

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The final state proposal [G. T. Horowitz and J. M. Maldacena, J. High Energy Phys. 04 (2004) 008JHEPFG1029-847910.1088/1126-6708/2004/04/008] is an attempt to relax the apparent tension between string theory and semiclassical arguments regarding the unitarity of black hole evaporation. Authors Bousso and Stanford [Phys. Rev. D 89, 044038 (2014)PRVDAQ1550-799810.1103/PhysRevD.89.044038] analyze thought experiments where an infalling observer first verifies the entanglement between early and late Hawking modes and then verifies the interior purification of the same Hawking particle. They claim that "probabilities for outcomes of these measurements are not defined" and therefore suggest that "the final state proposal does not offer a consistent alternative to the firewall hypothesis." We show, in contrast, that one may define all the relevant probabilities based on the so-called ABL rule [Y. Aharonov, P. G. Bergmann, and J. L. Lebowitz, Phys. Rev. 134, B1410 (1964)PHRVAO0031-899X10.1103/PhysRev.134.B1410], which is better suited for this task than the decoherence functional. We thus assert that the analysis of Bousso and Stanford cannot yet rule out the final state proposal.

Original languageEnglish
Article number088501
JournalPhysical Review D
Issue number8
StatePublished - 25 Apr 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 American Physical Society.


Dive into the research topics of 'Comment on Measurements without probabilities in the final state proposal'. Together they form a unique fingerprint.

Cite this