Dynamics of the quantum vacuum: Cosmology as relaxation to the equilibrium state

TL;DR

This paper explores how the quantum vacuum energy density evolves in an expanding universe, proposing a step-wise relaxation model that aligns with the decreasing matter density and may explain the small positive cosmological constant.

Contribution

It introduces a novel scenario of step-wise relaxation of vacuum energy density, linking it to neutrino contributions and universe expansion dynamics.

Findings

Vacuum energy density relaxes in steps over cosmic time

Current small positive cosmological constant may be due to neutrino effects

Model aligns vacuum relaxation with matter density decrease

Abstract

The behavior of the gravitating vacuum energy density in an expanding universe is discussed. A scenario is presented with a step-wise relaxation of the vacuum energy density. The vacuum energy density moves from plateau to plateau and follows, on average, the steadily decreasing matter energy density. The current plateau with a small positive value of the vacuum energy density (effective cosmological constant) may result from a still not equilibrated contribution of the light massive neutrinos to the quantum vacuum.