van de Bruck, C. orcid.org/0000-0001-8311-8941 and Daniel, R. (2021) Inflation and scale-invariant R2 gravity. Physical Review D, 103 (12). 123506. ISSN 2470-0010
Abstract
In scale-invariant models of fundamental physics, mass scales are generated by spontaneous symmetry breaking. In this work, we study inflation in scale-invariant R2 gravity, in which the Planck mass is generated by a scalar field, which is responsible for spontaneous breaking of scale symmetry. If the self-interactions of the scalar field are nonzero, a cosmological constant is generated, which can be potentially quite large. To avoid fine-tuning at late times, we introduce another scalar field which drives the classical cosmological constant to zero during inflation. Working in the Einstein frame, we find that due to a conserved Noether current, the corresponding three-field inflationary model (consisting of the two scalar fields plus the scalaron) becomes effectively a two-field model. The prize to be paid for introducing the field which cancels the classical cosmological constant at the end of inflation is that the running of the spectral index and the running of the running can be quite large due to entropy perturbations during inflation, making the model testable with future cosmological experiments.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 American Physical Society. This is an author-produced version of a paper subsequently published in Physical Review D. Uploaded in accordance with the publisher's self-archiving policy. |
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) |
Funding Information: | Funder Grant number SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/T001038/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 07 Feb 2022 11:48 |
Last Modified: | 08 Feb 2022 09:37 |
Status: | Published |
Publisher: | American Physical Society (APS) |
Refereed: | Yes |
Identification Number: | 10.1103/physrevd.103.123506 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:183338 |