Observational effects of the early episodically dominating dark energy

TL;DR

This paper explores how early episodic dark energy influences cosmological evolution and parameter estimation, revealing deviations from standard models and constraints from WMAP and Planck data.

Contribution

It introduces a scalar field dark energy model with episodic domination and analyzes its observational effects using CMB data, highlighting deviations from ΛCDM.

Findings

Early dark energy can significantly alter cosmological parameters.

Planck data strongly favors the ΛCDM model over episodic dark energy.

Episodic dark energy affects cosmic age and tensor perturbations.

Abstract

We investigate observational consequences of the early episodically dominating dark energy on the evolution of cosmological structures. For this aim, we introduce the minimally coupled scalar field dark energy model with the Albrecht-Skordis potential which allows a sudden ephemeral domination of dark energy component during the radiation or early matter era. The conventional cosmological parameters in the presence of such an early dark energy are constrained with WMAP and Planck cosmic microwave background radiation data including other external data sets. It is shown that in the presence of such an early dark energy the estimated cosmological parameters can deviate substantially from the currently known $\Lambda\textrm{CDM}$-based parameters, with best-fit values differing by several percents for WMAP and by a percent level for Planck data. For the latter case, only a limited amount of dark energy with episodic nature is allowed since the Planck data strongly favors the $\Lambda\textrm{CDM}$ model. Compared with the conventional dark energy model, the early dark energy dominating near radiation-matter equality or at the early matter era results in the shorter cosmic age or the presence of tensor-type perturbation, respectively. Our analysis demonstrates that the alternative cosmological parameter estimation is allowed based on the same observations even in Einstein's gravity.