The Well-Tempered Cosmological Constant: Fugue in B${}^{♭}$

Abstract

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.

15 pages, 3 figures

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• Well-Tempered Minkowski Solutions in Teleparallel Horndeski Theory
• A minimal self tuning model to solve the cosmological constant problem
• Self-tuning kinetic gravity braiding: Cosmological dynamics, shift symmetry, and the tadpole
• An Expansion of Well Tempered Gravity
• Tadpole Cosmology: Self Tuning Without Degeneracy
• Tadpole Cosmology: Milne Solution as a Cosmological Constant Hideout