A Graceful Exit for the Cosmological Constant Damping Scenario

Abstract

We present a broad and simple class of scalar-tensor scenarios that successfully realize dynamical damping of the effective cosmological constant, therefore providing a viable dynamical solution to the fine-tuning or "old" cosmological constant problem. In contrast to early versions of this approach, pioneered in the works of A. Dolgov in the 1980es, these do not suffer from unacceptable variations of Newton's constant, as one aims at a small but strictly positive (rather than zero) late-time curvature. In our approach, the original fine-tuning issue is traded for a hierarchy of couplings, and we further suggest a way to naturally generate this hierarchy based on fermion condensation and softly broken field shift symmetry.

arXiv commentv2: 16 pages, minor improvements, discussion added, typos corrected

References in corpus (21)

• Dynamics of dark energy
• The Case for a Positive Cosmological Lambda-term
• Everything You Always Wanted To Know About The Cosmological Constant Problem (But Were Afraid To Ask)
• General second order scalar-tensor theory, self tuning, and the Fab Four
• Quintessence and phantom cosmology with non-minimal derivative coupling
• Self-tuning and the derivation of the Fab Four
• The pion: an enigma within the Standard Model
• Higher spin fields and the problem of cosmological constant
• The cosmology of the Fab-Four
• The screening Horndeski cosmologies
• Fab 5: Noncanonical Kinetic Gravity, Self Tuning, and Cosmic Acceleration
• The Well-Tempered Cosmological Constant
• Possible solution to the main cosmological constant problem
• Ruling out a higher spin field solution to the cosmological constant problem
• Reconsidering a higher-spin-field solution to the main cosmological constant problem
• Vector-field model with compensated cosmological constant and radiation-dominated FRW phase
• Classical Cancellation of the Cosmological Constant Re-Considered
• Dynamical vacuum energy via adjustment mechanism
• Inflation from cosmological constant and nonminimally coupled scalar
• Nonminimal coupling and the cosmological constant problem
• Small dark energy without small parameters

Cited by in corpus (8)

• Well-tempered teleparallel Horndeski cosmology: a teleparallel variation to the cosmological constant problem
• Well-Tempered Cosmology
• The Well-Tempered Cosmological Constant: The Horndeski Variations
• Non-perturbative analysis for a massless minimal quantum scalar with $V(\varphi )=\lambda {\varphi }^4/4!+\beta {\varphi }^3/3!$ in the inflationary de Sitter spacetime
• The Well-Tempered Cosmological Constant: Fugue in B${}^{♭}$
• Screening and degenerate kinetic self-acceleration from the nonlinear freedom of reconstructed Horndeski theories
• Resummation of local and non-local scalar self energies via the Schwinger-Dyson equation in de Sitter spacetime
• Robustness of the Cosmological Constant Damping Mechanism Through Matter Eras