de Sitter attractors in generalized gravity

TL;DR

This paper derives conditions for the existence and stability of de Sitter solutions in generalized gravity theories, analyzing both homogeneous and inhomogeneous perturbations, with implications for early universe inflation and dark energy models.

Contribution

It provides a general framework for assessing de Sitter attractors in various gravity theories, including non-linear and scalar-tensor models, with stability criteria applicable to any coupling functions.

Findings

De Sitter attractors exist under specific conditions in generalized gravity.

Stability against inhomogeneous perturbations is established using a covariant formalism.

Implications for inflation and quintessence are discussed.

Abstract

We obtain conditions for the existence and stability of de Sitter attractors in the phase space of spatially homogeneous and isotropic cosmology in generalized theories of gravity (including non-linear and scalar-tensor theories). These conditions are valid for any form of the coupling functions of the theory. Stability with respect to inhomogeneous perturbations is analyzed using a covariant and gauge-invariant formalism. The relevance for inflationary scenarios of the early universe and for quintessence models of the present era is discussed.