Accelerated cosmos in a non-extensive setup

TL;DR

This paper explores a modified cosmological model where non-extensive entropy influences the universe's acceleration, leading to a geometrical fluid that can mimic dark energy and fit observational data.

Contribution

It introduces a non-extensive entropy framework into cosmology, deriving modified Friedmann equations and modeling dark energy as a geometrical fluid from non-extensive spacetime features.

Findings

The model can describe the current accelerated expansion of the universe.

Non-extensive features can generate a varying dark energy component.

The approach fits observational data on cosmic acceleration.

Abstract

Here, we consider a flat FRW universe whose its horizon entropy meets the R\'enyi entropy of non-extensive systems. In our model, the ordinary energy-momentum conservation law is not always valid. By applying the Clausius relation as well as the Cai-Kim temperature to the apparent horizon of a flat FRW universe, we obtain modified Friedmann equations. Fitting the model to the observational data on current accelerated universe, some values for the model parameters are also addressed. Our study shows that the current accelerating phase of universe expansion may be described by a geometrical fluid, originated from the non-extensive aspects of geometry, which models a varying dark energy source interacting with matter field in the Rastall way. Moreover, our results indicate that the probable non-extensive features of spacetime may also be used to model a varying dark energy source which does not interact with matter field, and is compatible with the current accelerated phase of universe.