Институт теоретической физики им. Л.Д. Ландау РАН
L.D. Landau Institute for Theoretical Physics RAS
Landau Days 2022 June, 27-30, 2022 Chernogolovka, Russia

New results in early Universe cosmology
Date/Time: 14:30 29-Jun-2022
Abstract:
New results in early Universe cosmology

Alexei A. Starobinsky

Landau Institute for Theoretical Physics RAS, Moscow - Chernogolovka, Russia



A brief review of 3 papers on the early Universe cosmology and its observational consequences published during the last academic year is presented. In the first paper, it is investigated if it is possible to realize a pre-inflationary stage of the isotropic Universe evolution with a regular bounce of its scale factor using scalar-tensor gravity with a potential being negative in some range. In the second paper, comparison is made between the calculation of the two-point correlation function of a light massive scalar field with the quartic self-interaction in the de Sitter background using a) the non-perturbative stochastic approach introduced by Starobinsky in eighties and b) the standard QFT in curved space-time approach at the two-loop level. In the third paper, a number of inflationary models having a non-scale-invariant behaviour of the primordial Fourier power spectrum of scalar perturbations at cosmological scales produced by a local feature in the inflation potential (e.g., by a rapid change in its first derivative near some point) are compared with existing observational data on CMB temperature anisotropy and polarization.

1. D. Polarski, A. A. Starobinsky, Y. Verbin. Bouncing cosmological isotropic solutions in scalar-tensor gravity. J. Cosm. Astropart. Phys. 2022, 052 (2022); arXiv:2111.07319,
2. A.Yu. Kamenshchik, A. A. Starobinsky, T. Vardanyan. Massive scalar field in de Sitter spacetime: a two-loop calculation and a comparison with the stochastic approach. European Physical Journal C 82, 345 (2022); arXiv:2109.05625.
3. D. K. Hazra, D. Paoletti, I. Debono, A. Shafieloo, G. F. Smoot, A. A. Starobinsky. Inflation story: slow-roll and beyond. J. Cosm. Astropart. Phys. 2112, 038 (2021); arXiv:2107.09460.

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Authors
Starobinsky Alexei A (Presenter)
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