Can we have inflation with Omega > 1?

• Main Author: Linde, Andrei
• Format: Text
• Language: unknown
• Published: arXiv 2003
• Subjects: Astrophysics astro-ph; General Relativity and Quantum Cosmology gr-qc; High Energy Physics - Phenomenology hep-ph; High Energy Physics - Theory hep-th; FOS Physical sciences; Rovaniemi
• Online Access: https://dx.doi.org/10.48550/arxiv.astro-ph/0303245; https://arxiv.org/abs/astro-ph/0303245

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 large density perturbations 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 percent one can obtain a semi-realistic model of a closed inflationary universe. The spectrum of density perturbations in this model may have a cut-off on the scale of the horizon. Similar approach may be valid in application to a compact inflationary universe with a nontrivial topology. : 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