Critical review of prevailing explanations for the emergence of classicality in cosmology

Abstract

There have been recent attempts at justifying, from first principles, and within the standard framework, the emergence of classical behavior in the post-inflationary cosmological context. Accounting for this emergence is an important issue, as it underlies the extraordinary empirical success of our current understanding of cosmology. In this work, we offer a critique of different efforts at explaining the emergence of classical behavior in cosmology within the standard framework. We argue that such endeavors are generically found lacking in conceptual clarity, as they invariably rely, either upon unjustified, implicit assumptions, or on circular logic. We conclude that, within the standard approach, the emergence of classical behavior in cosmology constitutes an unexplained phenomenon.

arXiv comment32 pages. Published version with additional section containing our reply to a note added in arXiv:2004.10684 in response to an earlier version of this paper

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• First Principles Numerical Demonstration of Emergent Decoherent Histories
• Enlightening the CSL model landscape in inflation
• Reconstruction of inflationary scenarios in non-conservative unimodular gravity
• Emergent universe revisited through the CSL theory
• Quantum cosmology of the flat universe via closed real-time path integral
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• A simple gravitational self-decoherence model
• A response to the Mucino-Okon-Sudarsky's Assessment of Relational Quantum Mechanics
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• Observational constraints on the second-order primordial power spectrum: Exploring a Continuous Spontaneous Localization inspired inflationary model
• A reply to Rovelli's response to our "Assessing Relational Quantum Mechanics''