Cosmological Signatures of the Interaction between Dark-Energy and Massive Neutrinos

TL;DR

This paper explores how interactions between massive neutrinos and a quintessence scalar field could explain the universe's late-time acceleration, analyzing cosmological perturbations and constraining model parameters with current observations.

Contribution

It develops a perturbation theory framework for neutrino-dark energy interactions and derives observational constraints on the coupling and neutrino masses.

Findings

Neutrino mass sum constrained to < 0.87 eV at 95% confidence

Interaction models can account for cosmic acceleration

Stability issues and scattering effects are discussed

Abstract

We investigate whether interaction between massive neutrinos and quintessence scalar field is the origin of the late time accelerated expansion of the universe. We present cosmological perturbation theory in neutrinos probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for the cosmic acceleration today. We consider several types of scalar field potentials and put constraints on the coupling parameter between neutrinos and dark energy. Assuming the flatness of the universe, the constraint we can derive from the current observation is $\sum m_{\nu} < 0.87 eV$ at the 95 % confidence level for the sum over three species of neutrinos. We also discuss on the stability issue of the our model and on the impact of the scattering term in Boltzmann equation from the mass-varying neutrinos.