A flat FLRW dark energy model in f(Q,C)-gravity theory with observational constraints

Abstract

In the recently suggested modified non-metricity gravity theory with boundary term in a flat FLRW spacetime universe, dark energy scenarios of cosmological models are examined in this study. An arbitrary function, $f(Q,C)=Q+\alpha C^2$, has been taken into consideration, where $Q$ is the non-metricity scalar, $C$ is the boundary term denoted by $C=\ddot{R}-Q$, and $\alpha$ is the model parameter, for the action that is quadratic in $C$. The Hubble function $H(z)=H_0{[c_1{(1+z)}^n+c_2]}^{\frac{1}{2}}$, where $H_0$ is the current value of the Hubble constant and $n,c_1$ and $c_2$ are arbitrary parameters with $c_1+c_2=1$, has been used to examine the dark energy characteristics of the model. We discovered a transit phase expanding universe model that is both decelerated in the past and accelerated in the present, and we discovered that the dark energy equation of state (EoS) ${\omega }^{(de)}$ behaves as $(-1\le {\omega }^{(de)}<2)$. The Om diagnostic analysis reveals the quintessence behavior in the present and the cosmological constant scenario in the late-time universe. Finally, we calculated the universe’s current age, which was found to be quite similar to recent data.