Neutrino Dark Energy -- Revisiting the Stability Issue
Abstract
A coupling between a light scalar field and neutrinos has been widely discussed as a mechanism for linking (time varying) neutrino masses and the present energy density and equation of state of dark energy. However, it has been pointed out that the viability of this scenario in the non-relativistic neutrino regime is threatened by the strong growth of hydrodynamic perturbations associated with a negative adiabatic sound speed squared. In this paper we revisit the stability issue in the framework of linear perturbation theory in a model independent way. The criterion for the stability of a model is translated into a constraint on the scalar-neutrino coupling, which depends on the ratio of the energy densities in neutrinos and cold dark matter. We illustrate our results by providing meaningful examples both for stable and unstable models.
Cite
@article{arxiv.0705.2018,
title = {Neutrino Dark Energy -- Revisiting the Stability Issue},
author = {Ole Eggers Bjaelde and Anthony W. Brookfield and Carsten van de Bruck and Steen Hannestad and David F. Mota and Lily Schrempp and Domenico Tocchini-Valentini},
journal= {arXiv preprint arXiv:0705.2018},
year = {2009}
}