Massive photon and dark energy

We investigate the cosmology of massive electrodynamics and explore the possibility whether the massive photon could provide an explanation of dark energy. The action is given by the scalar-vector-tensor theory of gravity, which is obtained by nonminimal coupling of the massive Stueckelberg QED with gravity; its cosmological consequences are studied by paying particular attention to the role of photon mass. We find that the theory allows for cosmological evolution where the radiation- and matter-dominated epochs are followed by a long period of virtually constant dark energy that closely mimics a ΛCDM model. We also find that the main source of the current acceleration is provided by the nonvanishing photon mass governed by the relation Λ∼m2. A detailed numerical analysis shows that the nonvanishing photon mass on the order of ∼10-34 eV is consistent with current observations. This magnitude is far less than the most stringent limit on the photon mass available so far, which is on the order of m≤10-27 eV.