2003/03/31 by Andrei Linde · 11 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Class (philosophy) #Cosmology #Cosmology and Gravitation Theories #De Sitter universe #Flatness (cosmology) #Galaxies: Formation, Evolution, Phenomena #Inflation (cosmology) #Inflationary epoch #Scale (ratio) #Scale factor (cosmology) #Universe #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2003/05/002
published as JCAP 0305:002,2003 · 8 pages, 4 figs., based on the talk given at the conference COSMO-01, September 4, 2001, Rovaniemi, Finland; discussion of the universes with nontrivial topology is extended
arxiv created 2003/04/01 · openalex publication_date 2003/05/08 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
It is very difficult to obtain a realistic model of a closed inflationary universe. Even if one fine-tunes the total number of e-folds to be sufficiently small, the resulting universe typically has δρ/ρ∼Δ T / T = O (1) on the scale of the horizon. We describe a class of models where this problem can be resolved. The models are unattractive and fine-tuned, so the flatness of the universe remains a generic prediction of inflationary cosmology. Nevertheless one should keep in mind that with the fine-tuning at the level of about one per cent one can obtain a semi-realistic model of an inflationary universe with Ω>1. The spectrum of density perturbations in this model may have a cut-off on the scale of the horizon. A similar approach may be valid in application to a compact inflationary universe with a nontrivial topology.