Tsallis holographic dark energy in the Brans-Dicke cosmology

TL;DR

This paper develops a holographic dark energy model using Tsallis entropy within Brans-Dicke cosmology, analyzing its stability and cosmic evolution with and without dark sector interactions.

Contribution

It introduces a novel holographic dark energy model based on Tsallis entropy in the Brans-Dicke framework, exploring effects of curvature and interactions.

Findings

Model's cosmic evolution is more flexible with curvature.

Both interacting and non-interacting models are classically unstable.

Classical stability and realistic cosmic behavior cannot be achieved simultaneously.

Abstract

Using the Tsallis generalized entropy, holographic hypothesis and also considering the Hubble horizon as the IR cutoff, we build a holographic model for dark energy and study its cosmological consequences in the Brans-Dicke framework. At first, we focus on a non-interacting universe, and thereinafter, we study the results of considering a sign-changeable interaction between the dark sectors of the cosmos. Our investigations show that, compared with the flat case, the power and freedom of the model in describing the cosmic evolution is significantly increased in the presence of the curvature. The stability analysis also indicates that, independent of the universe curvature, both the interacting and non-interacting cases are classically unstable. In fact, both the classical stability criterion and an acceptable behavior for the cosmos quantities, including the deceleration and density parameters as well as the equation of state, are not simultaneously obtainable.