Modified gravity and the stability of de Sitter space

TL;DR

This paper investigates the stability of de Sitter space in modified gravity theories and scalar-tensor models, finding that stability conditions differ between these frameworks and are crucial for understanding cosmic acceleration.

Contribution

It provides a gauge-independent analysis of de Sitter stability in modified gravity and scalar-tensor theories, clarifying the conditions for cosmic acceleration models.

Findings

Stability condition matches homogeneous perturbation analysis in modified gravity.

Scalar-tensor gravity has more restrictive stability conditions.

Stability criteria are essential for viable dark energy models.

Abstract

Within the context of modified gravity and dark energy scenarios of the accelerating universe, we study the stability of de Sitter space with respect to inhomogeneous perturbations using a gauge-independent formalism. In modified gravity the stability condition is exactly the same that one obtains from a homogeneous perturbation analysis, while the stability condition in scalar-tensor gravity is more restrictive.