Modeling a Non-Singular Universe with Late-Time Acceleration through a Novel Inhomogeneous Barotropic Equation of State (2504.16826v2)

Abstract: In this study, we investigated the effects of incorporating barotropic fluids on cosmological solutions within the general relativity (GR) framework. We proposed a modified version of the barotropic fluid with the EoS, $p=\zeta _0 \rho +\zeta _1 \rho \left(t-t_0\right){}^{-2 n}$, where $\zeta_0$, $\zeta_1$, $t_0$ and $n$ are some constants. Our goal is to explore if this type of EoS might help explain the universe's development, concentrating on the scenario where the universe bounces instead of singularities. Interestingly the generic solutions derived from our model are sufficiently adaptable to illustrate the bounce scenario, cosmic inflation and late-time dark-energy behaviour. The parameters $\zeta_0$, $\zeta_1$, $t_0$, and $n$ define the universe's phase in this non-singular solution. We investigated several elements of cosmic development, including as the energy density, deceleration parameter, and energy conditions, in order to validate our model. Stability analysis showed that the perturbations approach to zero as the time evolves, indicating the model is stable under scalar perturbation. Additionally, we looked at the statefinder diagnostics and Hubble flow dynamics to get more understanding of the model's dark energy and inflationary behaviour, respectively. Additionally, we conducted a study of the models' relevance to the observational datasets from BAO, DESI and Pantheon+SH0ES.