Observational Constraints on Dynamical Dark Energy Models

TL;DR

This paper reviews observational evidence for $\phi$CDM dynamical dark energy models, highlighting their differences from $\Lambda$CDM$, and discusses how recent data constrains these models, with $\Lambda$CDM$ still favored but many $\phi$CDM$ models viable.

Contribution

It provides a comprehensive review of observational constraints on $\phi$CDM models, emphasizing recent data and the ongoing viability of these models compared to $\Lambda$CDM$.

Findings

Recent measurements favor spatially flat $\Lambda$CDM.

Many $\phi$CDM models remain consistent with data.

Observational data has significantly tightened constraints over 20 years.

Abstract

$\phi$CDM models provide an alternative to the standard $\Lambda$CDM paradigm, while being physically better motivated. These models lead to a time-dependent speed of sound for dark energy that is difficult to replicate by $w$CDM parametrizations. We review the most up-to-date status of observational evidence for the $\phi$CDM models in this paper. We start with an overview of the motivation behind these classes of models, the basic mathematical formalism, and the different classes of models. We then present a compilation of recent results of applying different observational probes to constraining $\phi$CDM model parameters. Over the last twenty years, the precision of observational data has increased immensely, leading to ever tighter constraints. A combination of the recent measurements favors the spatially flat $\Lambda$CDM model, but a large class of $\phi$CDM models is still not ruled out.