A new $f(Q)$ cosmological model with $H(z)$ quadratic expansion

TL;DR

This paper introduces a novel $f(Q)$ gravity model with a quadratic $H(z)$ expansion that explains late-time cosmic acceleration, supported by observational data and stability analysis.

Contribution

The paper proposes a new $f(Q)$ cosmological model with a quadratic Hubble parameter, constrained by observational data, and demonstrates its stability and ability to describe cosmic acceleration.

Findings

The model reproduces late-time acceleration of the universe.

The constrained deceleration parameter is $q_0=-0.285\,\pm\,0.021$.

Stability analysis confirms the model's robustness.

Abstract

We present a new $f(Q)$ cosmological model capable of reproducing late-time acceleration, i.e. $f\left( Q\right) = \lambda_{0}\left( \lambda +Q\right) ^{n}$ by supporting certain parametrization of the Hubble parameter. By using observational data from Hubble, Pantheon, and Baryonic Acoustic Oscillations (BAO) dataset, we investigate the constraints on the proposed quadratic Hubble parameter $H(z)$. This proposal caused the Universe to transition from its decelerated phase to its accelerated phase. Further, the current constrained value of the deceleration parameter from the combined Hubble+Pantheon+BAO dataset is $q_{0}=-0.285\pm 0.021$, which indicates that the Universe is accelerating. We also analyze the evolution of energy density, pressure, and EoS parameters to infer the Universe's accelerating behavior. Finally, we use a stability analysis with linear perturbations to assure the model's stability.