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Title: A note on Boltzmann brains

Understanding the observed arrow of time is equivalent, under general assumptions, to explaining why Boltzmann brains do not overwhelm ordinary observers. It is usually thought that this provides a condition on the decay rate of every cosmologically accessible de Sitter vacuum, and that this condition is determined by the production rate of Boltzmann brains calculated using semiclassical theory built on each such vacuum. Here, we argue, based on a recently developed picture of microscopic quantum gravitational degrees of freedom, that this thinking needs to be modified. In particular, depending on the structure of the fundamental theory, the decay rate of a de Sitter vacuum may not have to satisfy any condition except for the one imposed by the Poincaré recurrence. Finally, the framework discussed here also addresses the question of whether a Minkowski vacuum may produce Boltzmann brains.
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  1. Univ. of California, Berkeley, CA (United States). Berkeley Center for Theoretical Physics, Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Tokyo (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (WPI), Todai Inst. for Advanced Study
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-05CH11231; PHY-1214644
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 749; Journal Issue: C; Journal ID: ISSN 0370-2693
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); National Science Foundation (NSF)
Country of Publication:
United States