Effective cosmological constant induced by stochastic fluctuations of Newton's constant

TL;DR

This paper proposes that quantum fluctuations in spacetime geometry cause stochastic variations in Newton's constant, leading to a dynamic dark energy component that explains the Universe's late-time acceleration without invoking vacuum energy.

Contribution

It introduces a model where quantum geometry effects induce stochastic fluctuations in Newton's constant, resulting in a time-dependent dark energy term in cosmological equations.

Findings

Stochastic fluctuations of Newton's constant can produce an effective cosmological constant.

Quantum geometry effects may explain late-time cosmic acceleration.

Dark energy emerges from spacetime fluctuations rather than vacuum energy.

Abstract

We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.