Testing the cosmic coincidence problem and the nature of dark energy - art. no. 141302

Dark energy models which alter the relative scaling behavior of dark energy and matter could provide a natural solution to the cosmic coincidence prob lem-why the densities of dark energy and dark matter are comparable today. A generalized class of dark energy models is introduced which allows noncan onical scaling of the ratio of dark matter and dark energy with the Roberts on-Walker scale factor a(t). We show that determining whether there is a co incidence problem, and the extent of cosmic coincidence, can be addressed b y several forthcoming experiments.