Solving the main cosmological puzzles with a generalized time varying vacuum energy
Research Center for Astronomy, Academy of Athens, 11527 Athens, Greece e-mail: email@example.com
Accepted: 12 October 2009
We study the dynamics of the FLRW flat cosmological models in which the vacuum energy density varies with time, . In particular, we investigate the dynamical properties of a generalized vacuum model, and we find that under certain circumstances the vacuum term in the radiation era varies as , while in the matter era we have up to and for . The confirmation of such a behavior would be of paramount importance because it could provide a solution to the cosmic coincidence problem as well as to the fine-tuning problem, without changing the well known (from the concordance Λ-cosmology) Hubble expansion.
Key words: cosmology: theory / methods: analytical
© ESO, 2009