Cosmology of the de Sitter Horndeski models

TL;DR

This paper investigates Horndeski gravity models with de Sitter solutions, analyzing their cosmological evolution, and finds that non-linear shift-symmetric models can match current observational data, offering insights into the cosmological constant problem.

Contribution

It introduces and analyzes two classes of Horndeski models, demonstrating that non-linear shift-symmetric models can produce viable cosmological backgrounds.

Findings

Non-linear shift-symmetric models align with observational data.

Linear models have limitations in matching observations.

Both model classes can have de Sitter critical points.

Abstract

Horndeski models with a de Sitter critical point for any kind of material content may provide a mechanism to alleviate the cosmological constant problem. We study the cosmological evolution of two classes of families - the linear models and the non-linear models with shift symmetry. We conclude that the latter models can deliver a background dynamics compatible with the latest observational data.