Dark Energy from graviton-mediated interactions in the QCD vacuum

TL;DR

This paper proposes that quantum gravity corrections to the QCD vacuum can dynamically generate the observed dark energy, linking non-perturbative QCD effects with gravitational interactions.

Contribution

It introduces a model where graviton-mediated quantum corrections to the QCD vacuum induce a cosmological constant consistent with dark energy observations.

Findings

Quantum corrections to Einstein equations depend on G and Λ_QCD.

Cancellation of QCD vacuum contributions occurs below 100 MeV.

The model yields a dark energy density matching observations.

Abstract

Adopting the hypothesis about the exact cancellation of vacuum condensates contributions to the ground state energy in particle physics to the leading order in graviton-mediated interactions, we argue that the observable cosmological constant can be dynamically induced by an uncompensated quantum gravity correction to them after the QCD phase transition epoch. To start with, we demonstrate a possible cancellation of the quark-gluon condensate contribution to the total vacuum energy density of the Universe at temperatures $T<100$ MeV without taking into account the graviton-mediated effects. In order to incorporate the latter, we then calculate the leading-order quantum correction to the classical Einstein equations due to metric fluctuations induced by the non-perturbative vacuum fluctuations of the gluon and quark fields in the quasiclassical approximation. It has been demonstrated that such a correction to the vacuum energy density has a form $\varepsilon_{\Lambda}\sim G \Lambda_{\rm QCD}^6$, where $G$ is the gravitational constant, and $\Lambda_{\rm QCD}$ is the QCD scale parameter. We analyze capabilities of this approach based on the synthesis between quantum gravity in quasiclassical approximation and theory of non-perturbative QCD vacuum for quantitative explanation of the observed Dark Energy density.