Degeneracy pressure of relic neutrinos and cosmic coincidence problem

TL;DR

This paper proposes a model where relic neutrinos form a degenerate sphere that acts as an effective cosmological constant, potentially explaining the universe's recent acceleration and resolving the coincidence problem.

Contribution

It introduces a novel model linking relic neutrino degeneracy pressure to cosmic acceleration and addresses the coincidence problem through a phase transition in a field theory framework.

Findings

Relic neutrinos can form a degenerate sphere influencing cosmic expansion.

The model naturally explains the timing of recent acceleration.

The coincidence problem is addressed within this neutrino-based framework.

Abstract

We consider the universe as a huge $\nu_R$-sphere formed with degenerate relic neutrinos and suggest that its constant energy density play a role of an effective cosmological constant. We construct the sphere as a bubble of true vacuum in a field theory model with a spontaneously broken U(1) global symmetry, and we interpret the sphere-forming time as the transition time for recent acceleration of the universe. The coincidence problem may be regarded as naturally resolved in this model, because the relic neutrinos can make the $\nu_R$-sphere at the recent past time during the matter-dominated era.