Perturbations in the relaxation mechanism for a large cosmological constant

Abstract

Recently, a mechanism for relaxing a large cosmological constant (CC) has been proposed [arxiv:0902.2215], which permits solutions with low Hubble rates at late times without fine-tuning. The setup is implemented in the LXCDM framework, and we found a reasonable cosmological background evolution similar to the LCDM model with a fine-tuned CC. In this work we analyse analytically the perturbations in this relaxation model, and we show that their evolution is also similar to the LCDM model, especially in the matter era. Some tracking properties of the vacuum energy are discussed, too.

18 pages, LaTeX; discussion improved, accepted by CQG

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• Evolution of cosmological perturbations in an RG-driven inflationary scenario
• The cosmological constant filter without big bang singularity
• The cosmological constant and the relaxed universe
• Scale-dependent gravity and covariant scale-setting