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

Understand

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.