Duration of inflation and conditions at the bounce as a prediction of effective isotropic loop quantum cosmolog

TL;DR

This paper predicts that loop quantum cosmology with a scalar field naturally leads to about 145 e-folds of inflation, providing a clear and testable prediction, and also constrains the Barbero-Immirzi parameter.

Contribution

It offers a probabilistic prediction for inflation duration in loop quantum cosmology and establishes a new upper limit on the Barbero-Immirzi parameter.

Findings

Probability sharply peaked around 145 e-folds of inflation

Consistent with minimal scalar field models

Derives a new upper limit on the Barbero-Immirzi parameter

Abstract

Loop quantum cosmology with a scalar field is known to be closely linked with an inflationary phase. In this article, we study probabilistic predictions for the duration of slow-roll inflation, by assuming a minimalist massive scalar field as the main content of the universe. The phase of the field in its "prebounce" oscillatory state is taken as a natural random parameter. We find that the probability for a given number of inflationary e-folds is quite sharply peaked around 145, which is consistent with the most favored minimum values. In this precise sense, a satisfactory inflation is therefore a clear prediction of loop gravity. In addition, we derive an original and stringent upper limit on the Barbero-Immirzi parameter. The general picture of inflation, superinflation, deflation, and superdeflation is also much clarified in the framework of bouncing cosmologies.