A new take on the inflationary quintessence

TL;DR

This paper proposes a novel approach to connect inflationary models with dark energy by coupling the inflaton to the cosmic neutrino background, allowing successful quintessence models without strict symmetry constraints.

Contribution

It introduces a flexible framework that extends inflationary models to include dark energy via neutrino coupling, bypassing the need for $ ext{Z}_2$ symmetry in the potential.

Findings

The model can incorporate dark energy into many inflationary scenarios.

Neutrino nuggets are explained as bound states from Yukawa interactions.

The approach maintains particle production mechanisms during inflation.

Abstract

The quintessence field coupled to the cosmic neutrino background (CNB) has been widely discussed as an alternative mechanism to address the coincidence problem. As it is well known, it is possible to extend such models to obtain quintessential inflation, that is, to incorporate inflationary stage as well. Taking an alternative route, one can start from the well established inflationary models and obtain successful quintessence models at the expense of coupling with the CNB. To Follow this route, we use a slightly reformulated model addressed in PRD95, 123521 (2017). This particular model assumes $\mathcal{Z}_2$ symmetry for both scalar field potential and coupling term, which then breaks down in course of the cosmological evolution. For our discussion, however, the $\mathcal{Z}_2$ symmetry of the potential is not mandatory the model to work. The conventional mechanism of particle production by the oscillating inflaton field (and their subsequent thermalization) remains operative. It is plain to see that the proposed construction can be easily applied for many successful models of inflation to incorporate dark energy at the expense of coupling with the CNB. We address the issue of neutrino nuggets from the quantum field theory point of view. Namely, these nuggets are considered as bound states caused basically by the Yukawa force, which arises in the framework of linear perturbation theory due to exchange of virtual quanta of quintessence field between the neutrinos.