Dynamic cancellation of a cosmological constant and approach to the Minkowski vacuum

TL;DR

This paper revisits the $q$-theory approach to the cosmological constant problem, showing that quantum backreaction and zero-point energies can dynamically cancel the cosmological constant, leading the universe towards a Minkowski vacuum with inflation-like features.

Contribution

It introduces modifications to $q$-theory accounting for quantum backreaction and zero-point energies, demonstrating a dynamical mechanism for approaching Minkowski space.

Findings

The modified $q$-theory leads to a steady approach to Minkowski vacuum.

The universe exhibits slow convergence with inflation-like horizon growth.

Attractor behavior is observed for a range of initial conditions.

Abstract

The $q$-theory approach to the cosmological constant problem is reconsidered. The new observation is that the effective classical $q$-theory gets modified due to the backreaction of quantum-mechanical particle production by spacetime curvature. Furthermore, a Planck-scale cosmological constant is added to the potential term of the action density, in order to represent the effects from zero-point energies and phase transitions. The resulting dynamical equations of a spatially-flat Friedmann-Robertson-Walker universe are then found to give a steady approach to the Minkowski vacuum, with attractor behavior for a finite domain of initial boundary conditions on the fields. The approach to the Minkowski vacuum is slow and gives rise to an inflation-type increase of the particle horizon.