Barrow holographic dark energy in the Brans-Dicke cosmology

TL;DR

This paper develops a holographic dark energy model within Brans-Dicke cosmology using Barrow entropy, showing that certain interactions can explain cosmic acceleration and stability depends on interaction type and parameters.

Contribution

It introduces a novel holographic dark energy model based on Barrow entropy in Brans-Dicke cosmology, analyzing its stability and observational consistency.

Findings

Sign-changeable interacting model can be stable with proper parameters

Linear interacting model always predicts a stable universe

Model can explain current accelerated expansion

Abstract

We construct a holographic model for dark energy in the Brans-Dicke cosmology by using the holographic principle considering the Barrow entropy instead of the standard Bekenstein-Hawking one. The former arises from the effort to account for quantum-gravitational effects in black-hole physics and, according to the gravity-thermodynamic conjecture, in the cosmological framework. In order to explore the cosmological consequences of our model, we consider the Hubble horizon as the IR cutoff. We investigate both the non-interacting and interacting cases with the sign-changeable and linear interactions, showing that they can explain the present accelerated phase of the Universe expansion, in contrast to the standard Holographic Dark Energy model. We then perform the classical stability analysis using the squared sound speed. We find that, whilst the non-interacting model is unstable against the small perturbations, the sign-changeable interacting one can be stable only for suitable values of the model parameters. On the other hand, the linear interacting model always predicts a stable Universe. The consistency of our model with cosmological observations is discussed.