De Angelis, M. and van de Bruck, C. orcid.org/0000-0001-8311-8941 (2023) Adiabatic and isocurvature perturbations in extended theories with kinetic couplings. Journal of Cosmology and Astroparticle Physics, 2023 (10). 023. ISSN 1475-7516
Abstract
The scalar field sector in low-energy effective field theories motivated by string theory often contains several scalar fields, some of which possess non-standard kinetic terms. In this paper we study theories with two scalar fields, in which one of the fields has a non-canonical kinetic term. The kinetic coupling is allowed to depend on both fields, going beyond the work in the literature, which usually considers the case of the coupling to depend on the other field only. Our aim is to study adiabatic and isocurvature perturbations in these extended theories. Our results show that the evolution equation for the curvature perturbation does not change when allowing the coupling to depend on both fields, while the effective mass of the entropy perturbation changes. We find expressions for the spectral index and its running at horizon crossing and at the end of inflation. We apply the formalism and study three phenomenological models, with different kinetic couplings.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Author(s). Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI: https://creativecommons.org/licenses/by/4.0/ |
Keywords: | cosmological perturbation theory; inflation; Inflation and CMBR theory |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 10 Oct 2023 14:35 |
Last Modified: | 04 Oct 2024 15:48 |
Published Version: | http://dx.doi.org/10.1088/1475-7516/2023/10/023 |
Status: | Published |
Publisher: | IOP Publishing |
Refereed: | Yes |
Identification Number: | 10.1088/1475-7516/2023/10/023 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:204089 |
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