Cosmological dynamics of extended chameleons

TL;DR

This paper studies the cosmological behavior of extended chameleon models, showing they can mimic dark energy and dark matter evolution without conflicting with standard cosmological observations.

Contribution

It provides a comprehensive dynamical systems analysis of extended chameleon models at both background and perturbation levels, confirming their viability as dark energy alternatives.

Findings

Late time transition from dark matter to dark energy is well described.

Models show no deviations from $\Lambda$CDM at background and perturbation levels.

Extended chameleons are confirmed as viable dark energy models.

Abstract

We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at the largest distances, while structure formation is analysed at sub-horizon scales within the quasi-static approximation. The late time dynamical transition from dark matter to dark energy domination can be well described by almost all extended chameleon models considered, with no deviations from $\Lambda$CDM results at both background and perturbation levels. The results obtained in this work confirm the cosmological viability of extended chameleons as alternative dark energy models.