Özet:

In this work, we study a homogeneous and isotropic cosmological model of the universe filled with the perfect fluid and scalar field. Using the framework of Brans-Dicke (BD) and Gauss-Bonnet (GB) theories of gravity, we obtain the field equations and find the expansion parameter and dynamical field functions. We suppose that an energy interaction occurs between the BD and GB components, then adopting this argument, we speculate that the BD scalar field may arise from the intrinsic properties of the GB medium. Also, we get the positive energy density and negative pressure for the baryonic part of matter, so we confirm that this property coincides with the dark energy behavior of the late time universe. We conclude that since some sort of interaction between the scalar field and GB sector provides the accelerating expansion of the universe, to recover the dark energy effect, we may no longer need a cosmological constant.

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