Dynamical coherent states and physical solutions of quantum cosmological bounces

TL;DR

This paper introduces an exactly solvable loop quantum cosmology model that explores quantum transitions through a cosmological bounce, highlighting the complex behavior of dynamical coherent states and their implications for early universe classicality.

Contribution

It presents a new solvable model for quantum cosmological bounces, analyzing dynamical coherent states and their evolution, which advances understanding of quantum gravity effects in cosmology.

Findings

Quantum fluctuations before and after the bounce are generally unrelated.

Classicality at late times does not guarantee classicality before the bounce.

Quantum states evolve deterministically through the bounce.

Abstract

A new model is studied which describes the quantum behavior of transitions through an isotropic quantum cosmological bounce in loop quantum cosmology sourced by a free and massless scalar field. As an exactly solvable model even at the quantum level, it illustrates properties of dynamical coherent states and provides the basis for a systematic perturbation theory of loop quantum gravity. The detailed analysis is remarkably different from what is known for harmonic oscillator coherent states. Results are evaluated with regard to their implications in cosmology, including a demonstration that in general quantum fluctuations before and after the bounce are unrelated. Thus, even within this solvable model the condition of classicality at late times does not imply classicality at early times before the bounce without further assumptions. Nevertheless, the quantum state does evolve deterministically through the bounce.