The well-tempered cosmological constant: fugue in B$^\flat

Zero point fluctuations of quantum fields should generate a large cosmological constant energy density in any spacetime. How then can we have anything other than de Sitter space without fine tuning? Well tempering—dynamical cancellation of the cosmological constant using degeneracy within the field...

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Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2020-12, Vol.2020 (12)
Main Authors: Appleby, Stephen, Linder, Eric V.
Format: Article
Language:English
Subjects:
ASTRONOMY AND ASTROPHYSICS
Online Access:Get full text
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Summary:Zero point fluctuations of quantum fields should generate a large cosmological constant energy density in any spacetime. How then can we have anything other than de Sitter space without fine tuning? Well tempering—dynamical cancellation of the cosmological constant using degeneracy within the field equations— can replace a large cosmological constant with a much lower energy state. Here we give an explicit mechanism to obtain a Minkowski solution, replacing the cosmological constant with zero, and testing its attractor nature and persistence through a vacuum phase transition. We derive the general conditions that Horndeski scalar-tensor gravity must possess, and evolve in a fugue of functions, to deliver nothing and make the universe be flat.
ISSN:1475-7516
1475-7516