Orateur
Description
The purpose of this research is to study cosmological effects of the coupling between dark energy and dark matter through the general conformal transformations in which the coefficient of conformal depends on both scalar field and its kinetic term. Using dynamical analysis, the influence of general conformal coupling on the evolution of background universe is investigated. We found that the evolution of background universe has scaling fixed point corresponds to acceleration of the universe at late time. For suitable choices of parameters, the universe can evolve from radiation dominated epoch to ø-matter dominated epoch and reaching to scaling fixed point at late time. The effective equation of state during ø-matter dominated epoch is slightly positive. Therefore, the $H_0$ tension can be alleviated. Also, the effective gravitational coupling for dark matter perturbations in this model can be smaller than in ΛCDM model. Then, the growth rate of dark matter perturbations is less than in ΛCDM model. Thus, the $\sigma_8$ tension can be alleviated.
