Palatini inflation in models with an R 2 term

Antoniadis, Ignatios; Karam, A.; Lykkas, A.; Tamvakis, K. (2018). Palatini inflation in models with an R 2 term. Journal of cosmology and astroparticle physics, 2018(11), 028. Institute of Physics Publishing IOP 10.1088/1475-7516/2018/11/028

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The Starobinsky model, considered in the framework of the Palatini formalism, in contrast to the metric formulation, does not provide us with a model for inflation, due to the absence of a propagating scalar degree of freedom that can play the role of the inflaton. In the present article we study the Palatini formulation of the Starobinsky model coupled, in general nonminimally, to scalar fields and analyze its inflationary behavior. We consider scalars, minimally or nonminimally coupled to the Starobinsky model, such as a quadratic model, the induced gravity model or the standard Higgs-like inflation model and analyze the corresponding modifications favorable to inflation. In addition we examine the case of a classically scale-invariant model driven by the Coleman-Weinberg mechanism. In the slow-roll approximation, we analyze the inflationary predictions of these models and compare them to the latest constraints from the Planck collaboration. In all cases, we find that the effect of the R² term is to lower the value of the tensor-to-scalar ratio.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Antoniadis, Ignatios

Subjects:

500 Science > 530 Physics

ISSN:

1475-7516

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Esther Fiechter

Date Deposited:

28 Dec 2018 14:00

Last Modified:

20 Nov 2019 02:30

Publisher DOI:

10.1088/1475-7516/2018/11/028

ArXiv ID:

1810.10418

BORIS DOI:

10.7892/boris.122110

URI:

https://boris.unibe.ch/id/eprint/122110

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