The well-tempered cosmological constant: the Horndeski variations

Well tempering is one of the few classical field theory methods for solving the original cosmological constant problem, dynamically canceling a large (possibly Planck scale) vacuum energy and leaving the matter component intact, while providing a viable cosmology with late time cosmic acceleration a...

Full description

Saved in:
Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2020-12, Vol.2020 (12), p.36-36
Main Authors: Appleby, Stephen, Linder, Eric V.
Format: Article
Language:English
Subjects:
Acceleration
Astronomical models
ASTRONOMY AND ASTROPHYSICS
Big Bang theory
Constraint modelling
Cosmological constant
Cosmology
Data analysis
Field theory
Gravitation
Stability criteria
Tensors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Well tempering is one of the few classical field theory methods for solving the original cosmological constant problem, dynamically canceling a large (possibly Planck scale) vacuum energy and leaving the matter component intact, while providing a viable cosmology with late time cosmic acceleration and an end de Sitter state. We present the general constraints that variations of Horndeski gravity models with different combinations of terms must satisfy to admit an exact de Sitter spacetime that does not respond to an arbitrarily large cosmological constant. We explicitly derive several specific scalar-tensor models that well temper and can deliver a standard cosmic history including current cosmic acceleration. Stability criteria, attractor behavior of the de Sitter state, and the response of the models to pressureless matter are considered. The well tempered conditions can be used to focus on particular models of modified gravity that have special interest— not only removing the original cosmological constant problem but providing relations between the free Horndeski functions and reducing them to a couple of parameters, suitable for testing gravity and cosmological data analysis.
ISSN:1475-7516
1475-7516
DOI:10.1088/1475-7516/2020/12/036