Generation of seed perturbations from Quantum Cosmology

TL;DR

This paper explores how quantum cosmology models can generate seed perturbations in the early universe, resulting in a scale-invariant power spectrum and predominantly isocurvature perturbations.

Contribution

It demonstrates that a quantum transition from flat spacetime can produce a flat FLRW universe with initial seed perturbations, including their spectral properties.

Findings

Generated perturbations are scale invariant at horizon crossing.

The seed perturbations are predominantly of the isocurvature type.

The model links quantum cosmology with observable universe features.

Abstract

The origin of seed perturbations in the Universe is studied within the framework of a specific minisuperspace model. It is shown that the `creation' of the Universe as a result of a quantum transition from a flat empty spacetime would lead to a flat FLRW (Friedmann Lema\^\i tre Robertson-Walker) Universe with weak inhomogeneous perturbations at large wavelengths. The power spectrum of these perturbations is found to be scale invariant at horizon crossing (i.e., the Harrison-Zeldovich spectrum). It is also recognised that the seed perturbations generated in our model would be generically of the isocurvature kind.