Linear and non-linear perturbations in dark energy models

TL;DR

This paper examines three time-dependent dark energy models by analyzing their background evolution and perturbations, finding that their non-linear effects on matter power spectra are similar to the standard Lambda Cold Dark Matter model.

Contribution

It provides a detailed analysis of linear and non-linear perturbations in three dark energy parameterisations, highlighting their similarities to the standard model.

Findings

Non-linear contributions are scale-independent across models.

Perturbation behavior closely matches the Lambda CDM predictions.

No significant deviations found in matter power spectra.

Abstract

In this work we discuss observational aspects of three time-dependent parameterisations of the dark energy equation of state $w(z)$. In order to determine the dynamics associated with these models, we calculate their background evolution and perturbations in a scalar field representation. After performing a complete treatment of linear perturbations, we also show that the non-linear contribution of the selected $w(z)$ parameterisations to the matter power spectra is almost the same for all scales, with no significant difference from the predictions of the standard $\Lambda$CDM model.