Backreaction in Growing Neutrino Quintessence

TL;DR

This paper uses numerical simulations to study how neutrino lumps affect cosmology in Growing Neutrino Quintessence, revealing strong backreaction effects that challenge models with constant coupling.

Contribution

It demonstrates the importance of field-dependent coupling in Growing Neutrino Quintessence to achieve realistic cosmological models.

Findings

Backreaction effects are very strong with constant coupling.

Realistic cosmology requires field-dependent coupling.

Large neutrino lumps can be observationally tested.

Abstract

We investigate the cosmological effects of neutrino lumps in Growing Neutrino Quintessence. The strongly non-linear effects are resolved by means of numerical N-body simulations which include relativistic particles, non-linear scalar field equations and backreaction effects. For the investigated models with a constant coupling between the scalar field and the neutrinos the backreaction effects are so strong that a realistic cosmology is hard to realize. This points towards the necessity of a field dependent coupling in Growing Neutrino Quintessence. In this case realistic models of dynamical Dark Energy exist which are testable by the observation or non-observation of large neutrino lumps.