Stability analysis of a dark energy model in Rastall gravity

TL;DR

This paper investigates a dark energy model within Rastall gravity using observational data and dynamical analysis, showing it transitions from dark matter-like behavior to quintessence dark energy, with implications for cosmic acceleration.

Contribution

It introduces a new cosmological model in Rastall gravity, constrains its parameters with MCMC, and validates its dynamics through independent analysis.

Findings

Model parameters constrained with uncertainties.

Transition from dark matter to dark energy behavior.

Violation of strong energy condition in late universe.

Abstract

We study a cosmological model in Rastall's theory of gravity in the framework of the flat FLRW metric. We formulate the value of the Hubble parameter, which contains two model parameters, $ \alpha $ and $ j $. Employing the Markov Chain Monte Carlo (MCMC) sampling technique, we determine the values of these model parameters along with their uncertainties. Moreover, we derive the equation of state (EoS) parameter, which converges around the quintessence region. We perform a dynamical system analysis using the linearization technique to validate the results independently. Also, we discuss various physical attributes of the model, highlighting the transition to acceleration and the violation of the strong energy condition (SEC) in the late stages of evolution. In conclusion, our model mimics the behavior of a dark matter fluid during the past epoch and transitions into a quintessence dark energy model in the future epoch.