The accelerated expansion of the Universe as a quantum cosmological effect

TL;DR

This paper demonstrates that quantum cosmological effects in a quantized FLRW model can induce an accelerated expansion phase, potentially explaining supernova observations without dark energy.

Contribution

It introduces a new class of gaussian quantum states in the Bohm-de Broglie framework that produce an accelerated expansion phase in quantum cosmology.

Findings

Quantum trajectories show a transition from decelerated to accelerated expansion.

Luminosity distance-redshift relation approximates classical models with a cosmological constant for z<1.

Quantum effects may account for observed cosmic acceleration.

Abstract

We study the quantized Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) model minimally coupled to a free massless scalar field. In a previous paper, \cite{fab2}, solutions of this model were constructed as gaussian superpositions of negative and positive modes solutions of the Wheeler-DeWitt equation, and quantum bohmian trajectories were obtained in the framework of the Bohm-de Broglie (BdB) interpretation of quantum cosmology. In the present work, we analyze the quantum bohmian trajectories of a different class of gaussian packets. We are able to show that this new class generates bohmian trajectories which begin classical (with decelerated expansion), undergo an accelerated expansion in the middle of its evolution due to the presence of quantum cosmological effects in this period, and return to its classical decelerated expansion in the far future. We also show that the relation between luminosity distance and redshift in the quantum cosmological model can be made close to the corresponding relation coming from the classical model suplemented by a cosmological constant, for $z<1$. These results suggest the posibility of interpreting the present observations of high redshift supernovae as the manifestation of a quantum cosmological effect.