Dark energy: a quantum fossil from the inflationary Universe?

TL;DR

This paper explores a possible quantum field theoretical link between dark energy and primordial inflation, proposing that a running gravitational coupling could explain the current accelerated expansion of the Universe.

Contribution

It introduces a novel mechanism based on quantum conformal symmetry that connects early Universe inflation with present-day dark energy through a running cosmological term.

Findings

Dark energy may originate from quantum effects linked to inflation.

A logarithmic, asymptotically-free running of gravitational coupling is proposed.

The model predicts a power-law variation of dark energy with redshift.

Abstract

The discovery of dark energy (DE) as the physical cause for the accelerated expansion of the Universe is the most remarkable experimental finding of modern cosmology. However, it leads to insurmountable theoretical difficulties from the point of view of fundamental physics. Inflation, on the other hand, constitutes another crucial ingredient, which seems necessary to solve other cosmological conundrums and provides the primeval quantum seeds for structure formation. One may wonder if there is any deep relationship between these two paradigms. In this work, we suggest that the existence of the DE in the present Universe could be linked to the quantum field theoretical mechanism that may have triggered primordial inflation in the early Universe. This mechanism, based on quantum conformal symmetry, induces a logarithmic, asymptotically-free, running of the gravitational coupling. If this evolution persists in the present Universe, and if matter is conserved, the general covariance of Einstein's equations demands the existence of dynamical DE in the form of a running cosmological term whose variation follows a power law of the redshift.