Observational Constraints on Dynamical Dark Energy Models

Understand

$\phi$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.