Quintom-like transit universe models in Metric-affine gravity
arXiv:2508.01770
Abstract
The current transit universe model is a precise solution to the equations of a new type of gravity theory called metric-affine gravity proposed in [Herko et al. \textit{Phys. Dark Univ.} \textbf{34} (2021) 100886]. This theory is the maximal extension of the most successful theory, ``General Relativity," by including the scalars, Ricci curvature , torsion , nonmetricity , and trace of the matter-energy-momentum tensor using a generalized connection called the ``metric-affine" connection. We obtain the modified field equations for a linear form of the function and for a flat, homogeneous, and isotropic FLRW spacetime universe. We find a hyperbolic solution and determine the constrained values of the model parameters using the latest observational data. We examine how certain cosmological factors, like the deceleration parameter , effective equation of state parameter , and dark energy equation of state parameter , vary over time to explain the properties of the observable universe. We perform the diagnostic test for the model, and it represents the phantom scenarios of the model. The behavior of the dark energy EoS parameter reveals the quintom-A-type universe characteristics.
19 pages, 6 figures