Quantum entanglement and non-Gaussianity in the primordial Universe

TL;DR

This paper introduces a novel quantum cosmology model that explores how quantum entanglement and non-Gaussian features emerge in the early universe's perturbations, potentially revealing signatures of quantum gravity.

Contribution

It develops a quantum model of the early universe without assuming separability, showing how entanglement and non-Gaussianity naturally arise in cosmological perturbations.

Findings

Quantum dynamics lead to entangled universe states.

Perturbations evolve into non-Gaussian states.

Model suggests observable quantum gravity signatures.

Abstract

We propose a new method to investigate signatures of a quantum gravity phase in the primordial state of cosmological perturbations. We formulate and study a quantum model of a perturbed Friedmann-Lemaitre-Robertson-Walker universe beyond a tensor-product Born-Oppenheimer-like factorization, that is, without restricting the wave function of the universe to the product of the background and perturbation wave functions. We show that the quantum dynamics generically does not preserve the product form of the universe's wave function, which spontaneously evolves into a more general entangled state. Upon expanding this state in a suitable basis of background wave functions and setting Gaussian initial conditions for the perturbations, we numerically find that each of these wave functions becomes associated with a non-Gaussian state of an inhomogeneous perturbation.