CPL effective dark energy from the backreaction effect

TL;DR

This paper models dark energy as an effect of small-scale inhomogeneities using the Buchert averaging approach, employing CPL parameterization, and compares the model with recent supernova and Hubble data to highlight differences from standard cosmology.

Contribution

It introduces a CPL-based backreaction dark energy model using effective geometry and tests it against observational data, revealing notable differences from standard models.

Findings

Backreaction model fits observational data.

Differences from standard FLRW cosmology.

Effective geometry influences dark energy modeling.

Abstract

In this paper, we interpret the dark energy as an effect caused by small scale inhomogeneities of the universe with the use of the spatial averaged approach of Buchert. The model considered here adopts the Chevallier-Polarski-Linder(CPL) parameterizations of the equation of state of the effective perfect fluid from the backreaction effect. Thanks to the effective geometry introduced by Larena et. al.\cite{larena2009testing} in their previous work, we confront such backreaction model with latest type Ia supernova and Hubble parameter observations, coming out with results that reveal the difference between the Friedmann-Lema\^{\i}tre-Robertson-Walker model and backreaction model.