# A Viable Dark Fluid Model

## TL;DR

This paper proposes a dark fluid cosmological model that interpolates between dust and dark energy states, constrained by observational data and theoretical conditions, providing exact solutions and insights into universe expansion.

## Contribution

Introduces a generalized dark fluid model based on an extended equation of state, with analytical solutions and observational constraints to describe cosmic evolution.

## Key findings

- Model can interpolate between dust and dark energy
- Parameters constrained by supernova data and causality conditions
- Exact solutions for luminosity distance and energy density evolution

## Abstract

We Consider a cosmological model based on a generalization of the equation of state proposed by Nojiri and Odintsov [46] and \v{S}tefan\v{c}i'c [47], [48]. We argue that this model works as a dark fluid model which can interpolate between dust equation of state and the dark energy equation of state. We show how the asymptotic behavior of the equation of state constrained the parameters of the model. The causality condition for the model is also studied to constrain the parameters and the fixed points are tested to determine different solution classes. Observations of Hubble diagram of SNe Ia supernovae are used to further constrain the model. We present an exact solution of the model and calculate the luminosity distance and the energy density evolution. We also calculate the deceleration parameter to test the state of the universe expansion.