Coupled quintessence with a possible transient accelerating phase

Resumo

We discuss cosmological consequences of a general model of coupled quintessence in which the phenomenological coupling between the cold dark matter and dark energy is a function of the cosmic scale factor (a). This class of models presents cosmological solutions in which the constitution of the Universe is dominated currently by an exotic component [X], but late future it come back to be dominated by cold dark matter. This dynamical behavior is completely different from the standard ?CDM evolution, and may alleviate some con?icts in reconciling the idea of the dark energy-dominated universe with observables in String/M-theory. Finally, we investigate some observational features of this model and discuss some constraints on its parameters from current SNe Ia, BAO, CMB and H0 data.