Constraints on the interaction strength in the model of interacting dynamical dark energy with linear and non-linear interacting terms

TL;DR

This paper constrains the interaction strength between dynamical dark energy and dark matter using observational data, introducing a novel non-linear interaction model that aligns better with local H0 measurements.

Contribution

It presents the first study of a non-linear interaction term in dynamical dark energy models, providing observational constraints and comparing them with previous models.

Findings

Non-linear interaction model shows better agreement with local H0 measurements.

Constraints on interaction parameters vary across models, with the non-linear model indicating a significant interaction.

The dynamical dark energy model is more physically consistent than previous interacting models.

Abstract

In this work the observational constraints on interaction coupling parameter between dynamical dark energy and cold dark matter were obtained using CMB, BAO and SN Ia data. The dark energy in considered models is dynamical and evolution of its equation of state parameter depends on dark coupling and internal properties of the dark energy. Such model is believed to be more physically consistent than models of interacting dark energy considered in previous works. Constraints were made for three types of interaction. The first two are the types which are often considered in other works on interacting dark energy. The third type has the non-linear dependence on densities of dark components and is studied for the first time. Observational constraints on Hubble constant $H_{0}$ for the first two models are in strong disagreement with so called local measurements of $H_{0}$. And the third model is in better agreement with local measurements than $\Lambda$CDM model. Also for the last non-linear model existence of non-zero interaction was found at greater than $1\sigma$ significance level.