Dissecting kinetically coupled quintessence: phenomenology and observational tests

TL;DR

This paper explores a dark energy model where the scalar field's kinetic term interacts with dark matter, analyzing its effects on cosmic evolution and testing it against observational data to constrain the interaction strength.

Contribution

It introduces a kinetically coupled quintessence model with observable signatures and performs parameter estimation, providing constraints on the coupling parameter using current cosmological data.

Findings

Coupling parameter constrained to be around 10^{-4}

No statistical preference over standard CDM model

Identifies measurable signatures in CMB and matter power spectra

Abstract

We investigate an interacting dark energy model which allows for the kinetic term of the scalar field to couple to dark matter via a power-law interaction. The model is characterised by scaling solutions at early times, which are of high interest to alleviate the coincidence problem, followed by a period of accelerated expansion. We discuss the phenomenology of the background evolution and of the linear scalar perturbations and we identify measurable signatures of the coupling in the dark sector on the cosmic microwave background, the lensing potential auto-correlation and the matter power spectra. We also perform a parameter estimation analysis using data of cosmic microwave background temperature, polarisation and lensing, baryonic acoustic oscillations and supernovae. We find that the strength of the coupling between the dark sectors, regulated by the parameter $\alpha$, is constrained to be of order $10^{-4}$. A model selection analysis does not reveal a statistical preference between $\Lambda$CDM and the Kinetic model.