Scaling dark energy in a five-dimensional bouncing cosmological model

摘要

We consider a five-dimensional Ricci flat bouncing cosmological model in which the four-dimensional induced matter contains two components at late times - the cold dark matter (CDM) + baryons and dark energy. We find that the arbitrary function f(z) contained in the solution plays a similar role as the potential V (0) in quintessence and phantom dark energy models. To resolve the coincidence problem, it is generally believed that there is a scaling stage in the evolution of the universe. We analyze the condition for this stage and show that a hyperbolic form of the function f (z) can work well in this property. We find that during the scaling stage (before z;z 2), the dark energy behaves like (but not identical to) a cold dark matter with an adiabatic sound speed c(s)(2) approximate to 0 and p(x) approximate to 0. After z approximate to 2, the pressure of the dark energy becomes negative. The transition from deceleration to acceleration happens at z(T) approximate to 0.8 which, as well as other predictions of the 5D model, agrees with current observations.