Non-Gaussianities as a Signature of Quantumness of Quantum Cosmology

Fuente: arXiv
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Auteurs principaux: Bergeron, Hervé, Małkiewicz, Przemysław, Peter, Patrick
Format: Preprint
Publié: 2025
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author Bergeron, Hervé
Małkiewicz, Przemysław
Peter, Patrick
author_facet Bergeron, Hervé
Małkiewicz, Przemysław
Peter, Patrick
contents We show that the consistent application of the rules of quantum mechanics to cosmological systems inevitably results in the so-called multiverse states in which neither the background spacetime nor the inhomogeneous perturbation are in definite states. We study the multiverse states as perturbations to the usually employed so-called Born-Oppenheimer states that are products of a wave function of the background and a wave function of the perturbation. The obtained corrections involve integrals over \emph{virtual backgrounds} that represent the effect of quantum background fluctuations on the perturbation state. They resemble loop corrections in quantum field theory. This approach demonstrates the inevitable existence of very specific non-Gaussian features in primordial fluctuations. We express the resulting non-Gaussian perturbation as a nonlinear function of the Gaussian perturbation obtained within the Born-Oppenheimer approximation, and compute its trispectrum, to show that the multiverse scenario leads to testable and distinct signatures in cosmological perturbations. Our approach applies both to inflationary and alternative cosmologies.
format Preprint
id arxiv_https___arxiv_org_abs_2503_14570
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-Gaussianities as a Signature of Quantumness of Quantum Cosmology
Bergeron, Hervé
Małkiewicz, Przemysław
Peter, Patrick
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
We show that the consistent application of the rules of quantum mechanics to cosmological systems inevitably results in the so-called multiverse states in which neither the background spacetime nor the inhomogeneous perturbation are in definite states. We study the multiverse states as perturbations to the usually employed so-called Born-Oppenheimer states that are products of a wave function of the background and a wave function of the perturbation. The obtained corrections involve integrals over \emph{virtual backgrounds} that represent the effect of quantum background fluctuations on the perturbation state. They resemble loop corrections in quantum field theory. This approach demonstrates the inevitable existence of very specific non-Gaussian features in primordial fluctuations. We express the resulting non-Gaussian perturbation as a nonlinear function of the Gaussian perturbation obtained within the Born-Oppenheimer approximation, and compute its trispectrum, to show that the multiverse scenario leads to testable and distinct signatures in cosmological perturbations. Our approach applies both to inflationary and alternative cosmologies.
title Non-Gaussianities as a Signature of Quantumness of Quantum Cosmology
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2503.14570