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Saving the universe with finite volume effects

Research output: Contribution to journalArticle

Original languageEnglish
Article number103522
JournalPhysical Review D (Particles, Fields, Gravitation and Cosmology)
Volume100
Issue number10
DOIs
Published15 Nov 2019

Bibliographical note

8 pages, 2 figures, comments and references added

King's Authors

Abstract

Setting aside anthropic arguments, there is no reason why the Universe should initially favor a net expanding phase rather than one experiencing a net contraction. However, a collapsing universe containing "normal" matter will end at a singularity in a finite time. We point out that there is a mechanism, derived from nonperturbative effects in quantum field theory in a finite volume, which may provide a bias toward expansion when the spacetime volume shrinks, by dynamically violating the null energy condition, without the need for modified gravity or exotic matter. We describe a scalar field component subjected to this nonperturbative effect in a cosmological background and consider its impact on a contracting phase. We discuss how this could dynamically generate the necessary initial conditions for inflation to get started, or form part of the mechanism for a nonsingular cosmological bounce.

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