Does Quantum Cosmology Predict a Constant Dilatonic Field?

TL;DR

This paper investigates a quantum cosmological model derived from string theory, showing that under certain conditions, the dilatonic field remains constant and the universe undergoes a bounce, avoiding singularities.

Contribution

It demonstrates that quantum cosmology can predict a constant dilatonic field and a bounce in the universe's evolution within a string-inspired framework.

Findings

The dilatonic field remains constant under natural assumptions.

The model predicts a bounce, avoiding singularities.

The minimum scale factor relates to gravitational coupling.

Abstract

Quantum cosmology may permit to determine the initial conditions of the Universe. In particular, it may select a specific model between many possible classical models. In this work, we study a quantum cosmological model based on the string effective action coupled to matter. The Schutz's formalism is employed in the description of the fluid. A radiation fluid is considered. In this way, a time coordinate may be identified and the Wheeler-DeWitt equation reduces in the minisuperspace to a Schr\"odinger-like equation. It is shown that, under some quite natural assumptions, the expectation values indicate a null axionic field and a constant dilatonic field. At the same time the scale factor exhibits a bounce revealing a singularity-free cosmological model. In some cases, the mininum value of the scale factor can be related to the value of gravitational coupling.