Narrow Results

In the field of theoretical physics, the fundamental characteristics and evolutionary mechanism of dark energy remain a subject of ongoing enquiry. While the simplest explanation for dark energy within General Relativity Theory is the cosmological constant, this concept faces a significant challenge known as the fine-tuning problem. In this study, we adopt an alternative approach, where we attribute the evolution of dark energy to the gravitational sector rather than the matter source. We explore the recently proposed theory of gravity known as modified symmetric teleparallel gravity, $f(Q)$, in which gravitational interactions are governed by the non-metricity term Q. Within this manuscript, we consider $f(Q)=\alpha Q^{\beta }$ that incorporates nonlinear forms of the non-metricity scalar, where $\alpha$ and $\beta$ are free model parameters. Subsequently, we determine the values of these model parameters that align with the observed values of cosmographic parameters. Our analysis delves into the behavior of various cosmological parameters, including the deceleration parameter, density, and equation of state parameters, as well as the cosmological distances for our cosmological model.

Stability, dark energy (DE) parameterization and swampland aspects for the Bianchi form-$V{I}_h$ universe have been formulated in an extended gravity hypothesis. Here, we have assumed a minimally coupled geometry field with a rescaled function of $f(R,T)$ replaced in the geometric action by the Ricci scalar $R$. Exact solutions are sought under certain basic conditions for the related field equations. For the following theoretically valid premises, the field equations in this scalar-tensor theory have been solved. It is observed under appropriate conditions that our model shows a decelerating to accelerating phase transition property. Results are observed to be coherent with recent observations. Here, our models predict that the universe’s rate of expansion will increase with the passage of time. The physical and geometric aspects of the models are discussed in detail. In this model, we also analyze the parameterizations of DE by fitting the EoS parameter $\omega (z)$ with redshift. The results obtained would be useful in clarifying the relationship between DE parameters. In this, we also explore the correspondence of quintessence DE with swampland criteria. The swampland criteria have been also shown the nature of the scalar field and the potential of the scalar field.