New Tsallis Holographic Dark Energy

TL;DR

This paper introduces a new holographic dark energy model based on Tsallis entropy, providing analytical expressions for cosmological parameters and analyzing the universe's thermal history and phase transition.

Contribution

It develops a novel Tsallis holographic dark energy model using the Tsallis entropy and future event horizon, with analytical solutions for key cosmological parameters.

Findings

Equation of state varies with parameter c, showing quintessence or quintom behavior.

The universe transitions from deceleration to acceleration around redshift z ≈ 0.6.

Model recovers ΛCDM behavior for c=1.

Abstract

Tsallis entropy is a generalization of the Boltzmann-Gibbs entropy in statistical theory which uses a parameter $\delta$ to measure the deviation from the standard scenario quantitatively. Using concepts of Tsallis entropy and future event horizon, we construct a new Tsallis holographic dark energy model. The parameters $c$ and $\delta$ will be used to characterize various aspects of the model. Analytical expressions for various cosmological parameters such as the differential equation describing the evolution of the effective dark energy density parameter, the equation of state parameter and the deceleration parameter are obtained. The equation of state parameter for the current model exhibits the pure quintessence behaviour for $c>1$, quintom behaviour for $c<1$ whereas the $\Lambda$CDM model is recovered for $c=1$. To analyze the thermal history of the universe, we obtained the expression for the deceleration parameter and found that for $z \approx 0.6$, the phase transits from deceleration to acceleration.