Loop quantum cosmology: From pre-inflationary dynamics to observations

TL;DR

This paper reviews how loop quantum cosmology connects Planck-scale quantum gravity effects with observable features in the early universe, especially regarding pre-inflationary dynamics and large-scale anomalies.

Contribution

It summarizes recent advances in loop quantum cosmology that enable concrete predictions linking quantum gravity to cosmological observations.

Findings

Resolution of the big bang singularity.

Concrete calculations of pre-inflationary effects.

Potential explanations for large-scale anomalies.

Abstract

The Planck collaboration has provided us rich information about the early universe, and a host of new observational missions will soon shed further light on the `anomalies' that appear to exist on the largest angular scales. From a quantum gravity perspective, it is natural to inquire if one can trace back the origin of such puzzling features to Planck scale physics. Loop quantum cosmology provides a promising avenue to explore this issue because of its natural resolution of the big bang singularity. Thanks to advances over the last decade, the theory has matured sufficiently to allow concrete calculations of the phenomenological consequences of its pre-inflationary dynamics. In this article we summarize the current status of the ensuing two-way dialog between quantum gravity and observations.