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Disformally coupled inflation
Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
Number of Authors: 3
2016 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, no 3, 006Article in journal (Refereed) Published
Abstract [en]

A disformal coupling between two scalar fields is considered in the context of cosmological inflation. The coupling introduces novel derivative interactions mixing the kinetic terms of the fields but without introducing superluminal or unstable propagation of the two scalar fluctuation modes. Though the typical effect of the disformal coupling is to inhibit one of the fields from inflating the universe, the energy density of the other field can drive viable near Sitter-inflation in the presence of nontrivial disformal dynamics, in particular when one assumes exponential instead of power-law form for the couplings. The linear perturbation equations are written for the two-field system, its canonical degrees of freedom are quantised, their spectra are derived and the inflationary predictions are reported for numerically solved exponential models. A generic prediction is low tensor-to-scalar ratio.

Place, publisher, year, edition, pages
2016. no 3, 006
Keyword [en]
cosmology with extra dimensions, inflation, string theory and cosmology, physics of the early universe
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:su:diva-130975DOI: 10.1088/1475-7516/2016/03/006ISI: 000375608200008OAI: diva2:936261
Available from: 2016-06-13 Created: 2016-06-09 Last updated: 2016-06-13Bibliographically approved

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Koivisto, Tomi
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Nordic Institute for Theoretical Physics (Nordita)
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