A Possible Connection Between Massive Fermions and Dark Energy

TL;DR

This paper explores how dense clouds of massive fermions interacting via a light scalar field could produce an effective negative pressure, potentially explaining dark energy within cosmological models.

Contribution

It proposes a novel mechanism linking massive fermions and scalar fields to dark energy, with implications for neutrinos and supersymmetric particles.

Findings

Effective fermion mass can become negligible in dense clouds.

Expansion of the universe can increase energy density and negative pressure.

Consistency with current dark energy observations for certain fermions.

Abstract

In a dense cloud of massive fermions interacting by exchange of a light scalar field, the effective mass of the fermion can become negligibly small. As the cloud expands, the effective mass and the total energy density eventually increase with decreasing density. In this regime, the pressure-density relation can approximate that required for dark energy. We apply this phenomenon to the expansion of the Universe with a very light scalar field and infer relations between the parameters available and cosmological observations. Majorana neutrinos at a mass that may have been recently determined, and fermions such as the Lightest Supersymmetric Particle (LSP) may both be consistent with current observations of dark energy.