Dark energy from the motions of neutrinos

TL;DR

This paper proposes a novel mechanism where neutrino interactions can induce a scalar field to freeze, mimicking dark energy and potentially resolving the coincidence problem without instabilities.

Contribution

It introduces a new model of dark energy based on neutrino-scalar interactions that trigger field freezing, independent of potential shape.

Findings

Scalar field can freeze due to energy exchange with neutrinos.

Neutrino motions can naturally trigger dark energy-like behavior.

Model avoids instabilities of previous mass-varying neutrino theories.

Abstract

We demonstrate that a scalar field is unable to reverse its direction of motion while continuously exchanging energy with another fluid. If the rate of transfer is modulated by the scalar's acceleration, the field can undergo a rapid process of freezing, despite being displaced from the local minimum of its potential. This enables dark energy to form from any potential, regardless of its shape. The field's equation of state mimicks that of a cosmological constant. We present a physically motivated realisation in the form of a derivative neutrino-majoron coupling. Coherent motions, which form only once the neutrinos become non-relativistic, could be responsible for instigating the freezing process. This would provide a natural resolution to the dark energy coincidence problem, while avoiding the dynamical instabilities associated with mass-varying neutrino models. Finally we discuss possible means by which this model could be experimentally verified.