http://arxiv.org/abs/1512.04580
We investigate modified gravity cosmological model $f(R)=R+\gamma R^2$ in Palatini formalism. We consider the universe filled with the Chaplygin gas and baryonic matter. The dynamics is reduced to the 2D sewn dynamical system of a Newtonian type. For this aim we use dynamical system theory. We classify all evolutional paths in the model as well as trajectories in the phase space. We demonstrate that the presence of a degenerate freeze singularity (glued freeze type singularities) is a generic feature of early evolution of the universe. We point out that a degenerate type III of singularity can be considered as an endogenous model of inflation between the matter dominating epoch and the dark energy phase. We also investigate cosmological models with negative $\gamma$. It is demonstrated that $\gamma$ equal zero is a bifurcation parameter and dynamics qualitatively changes in comparison to positive $\gamma$. Instead of the big bang the sudden singularity appears and there is a generic class of bouncing solutions sewn along the line of sewing.
M. Szydlowski, A. Stachowski, A. Borowiec, et. al.
Wed, 16 Dec 15
60/69
Comments: 21 pages, 14 figures
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