Dark energy interacting with neutrinos and dark matter: a phenomenological theory

Abstract

A model for a flat homogeneous and isotropic Universe composed of dark energy, dark matter, neutrinos, radiation and baryons is analyzed. The fields of dark matter and neutrinos are supposed to interact with the dark energy. The dark energy is considered to obey either the van der Waals or the Chaplygin equations of state. The ratio between the pressure and the energy density of the neutrinos varies with the red-shift simulating massive and non-relativistic neutrinos at small red-shifts and non-massive relativistic neutrinos at high red-shifts. The model can reproduce the expected red-shift behaviors of the deceleration parameter and of the density parameters of each constituent.The recent astronomical measurements of type-IA supernovae [1-4] and the analysis of the power spectrum of the CMBR [5-9] provided strong evidence for a present accelerated expansion of the Universe [3,10-14]; the nature of the responsible entity, called dark energy, still remains unknown. Furthermore, the measurements of the rotation curves of spiral galaxies [15] as well as other astronomical experiments suggest that the luminous matter represents only a small amount of the massive particles of the Universe, and that the more significant amount is related to dark matter. That offered a new setting for cosmological models with dark energy and dark matter and in these contexts many interesting phenomenological models appear in the literature analyzing the interaction of neutrinos [16][17][18] and dark matter [19-24] with dark energy. With respect to dark energy some exotic equations of state were proposed in the literature and among others we quote the van der Waals [25-29] and the Chaplygin [30-33] equations of state. Dedicated to Professor Ingo Müller on the occasion of his seventieth birthday.

Bulk Viscous Cosmological Model with Interacting Dark Fluids

“…This may also alleviate the coincidence problem, since an appropriate choice of the interaction term makes the ratio between the energy densities of the matter field and dark energy nearly constant at low red shifts. Several cosmological models have been proposed with interacting dark components; see [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] for examples. On the other hand, irreversible processes in the evolution of the Universe may also contribute significantly to alleviate the coincidence problem.…”

The effects of spatial curvature on cosmic evolution

“…(4) is used in a cosmological setting, w is often identified with the constant of proportionality in the conventional barotropic formula p m = wρ m , because this is essentially the form that (4) takes for small values of ρ m . 35 It is also common practice to reduce the number of free parameters by setting ρ c m = p c m = 1. The VdW EoS can then be rewritten concisely as: 35…”

Nonbaryonic dark matter and scalar field coupled with a transversal interaction plus decoupled radiation

“…However, from a theoretical point of view, it is reasonable to expect that dark components can interact with other fluids of the universe substantially in the very beginning of its evolution due to process occurred in the early universe. For instance, dark energy interacting with neutrinos was investigated in [46]. The framework of many interacting components could provide a more natural arena for studying the stringent bounds of dark energy at recombination epoch.…”