Exploring Cosmological Consequences and Viability of Varying G and Λ with Deceleration Parameter
Abstract
We give a brief review of a spatially homogeneous and anisotropic Bianchi Type-I cosmological model with varying gravitational constant G(t) and cosmological term Λ(t). The Einstein field equations are solved by considering a time-dependent deceleration parameter(DP) and barotropic equation of state (EoS) p=Wρ. The model universe is fit with a scale factor of the form ɑ(t) = (eAζct - 1)1/ζc which provides a smooth evolution from a decelerating to an accelerating phase of cosmic expansion. Analytical expressions for the pressure, energy density, G(t) and Λ(t) are derived and their variations with redshift are analyzed. The behaviour of cosmological parameters such as the Hubble function H(z), deceleration parameter q(z), jerk parameter J(z) and Om(z) diagnostic are examined. The present values H0 = 67.112+0.049-0.11 km s-1Mpc-1, q0 = -0.2926 and transition redshift zt = 0.8626 are obtained, consistent with recent observations. Overall, the proposed variable G and Λ Bianchi Type-I model provides a coherent description of the universe’s transition from deceleration to acceleration, consistent with 46 OHD.
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