Neutrino Dark Energy With More Than One Neutrino Species

Understand

The mass varying neutrino scenario is a model that successfully explains the origin of dark energy while at the same time solves the coincidence problem.

• The model is, however, heavily constrained by its stability towards the formation of neutrino bound states when the neutrinos become nonrelativistic.
• We discuss these constraints and find that natural, adiabatic, stable models with the right amount of dark energy today do not exist.
• Secondly, we explain why using the lightest neutrino, which is still relativistic, as an explanation for dark energy does not work because of a feedback mechanism from the heavier neutrinos.