2008/04/05 by Ramon Lapiedra, Ramón Lapiedra, D. Sáez +1
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc
paper · pdf · doi:10.1103/physrevd.77.104011
published as Phys.Rev.D77:104011,2008 · 22 pages, accepted for publication in Phys. Rev. D
arxiv created 2008/04/05 · openalex publication_date 2008/05/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss whether some perturbed Friedmann-Robertson-Walker (FRW) universes could be creatable, i.e., could have vanishing energy, linear momentum, and angular momentum, as it could be expectable if the Universe arose as a quantum fluctuation. On account of previous results, the background is assumed to be either closed (with very small curvature) or flat. In the first case, fully arbitrary linear perturbations are considered, whereas in the flat case, we assume the existence of the following: (i) inflationary scalar perturbations, that is to say, Gaussian adiabatic scalar perturbations having an spectrum close to the Harrison-Zel'dovich one, and (ii) arbitrary tensor perturbations. We conclude that any closed perturbed universe is creatable, and also that, irrespective of the spectrum and properties of the inflationary gravitational waves, perturbed flat FRW universes with standard inflation are not creatable. Some considerations on preinflationary scalar perturbations are also presented. The creatable character of perturbed FRW universes is studied, for the first time, in this paper.