Investigating $f(R)$-Inflation: background evolution and constraints

Fuente: arXiv
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Main Authors: Fazzari, Elisa, De Leo, Chiara, Montani, Giovanni, Martinelli, Matteo, Melchiorri, Alessandro, Cañas-Herrera, Guadalupe
Format: Preprint
Published: 2025
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author Fazzari, Elisa
De Leo, Chiara
Montani, Giovanni
Martinelli, Matteo
Melchiorri, Alessandro
Cañas-Herrera, Guadalupe
author_facet Fazzari, Elisa
De Leo, Chiara
Montani, Giovanni
Martinelli, Matteo
Melchiorri, Alessandro
Cañas-Herrera, Guadalupe
contents In this work, we investigate the possibility of generating an inflationary mechanism within the framework of a metric-$f(R)$ modified gravity theory, formulated in the Jordan frame. We explore whether the scalar field, non-minimally coupled to gravity and emerging in the Jordan frame, can play the role of the primordial inflaton. Particular attention is devoted to constructing a dynamical scenario in the Jordan frame that exhibits a slow-rolling phase for the scalar field and admits a quasi-de Sitter solution for cosmic evolution. To ensure consistency with the standard cosmological model, we impose a matching condition with the $Λ$CDM model at the end of the inflationary phase. Furthermore, to address the problem of the absence of matter after inflation, we consider a radiation-type particle creation process that maintains an approximately constant energy density. We test our theoretical model against background observational data, specifically Pantheon+ calibrated with SH0ES and DESI calibrated with BBN. We asses its viability and discuss implications for alleviating the Hubble constant tension.
format Preprint
id arxiv_https___arxiv_org_abs_2507_13890
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Investigating $f(R)$-Inflation: background evolution and constraints
Fazzari, Elisa
De Leo, Chiara
Montani, Giovanni
Martinelli, Matteo
Melchiorri, Alessandro
Cañas-Herrera, Guadalupe
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
In this work, we investigate the possibility of generating an inflationary mechanism within the framework of a metric-$f(R)$ modified gravity theory, formulated in the Jordan frame. We explore whether the scalar field, non-minimally coupled to gravity and emerging in the Jordan frame, can play the role of the primordial inflaton. Particular attention is devoted to constructing a dynamical scenario in the Jordan frame that exhibits a slow-rolling phase for the scalar field and admits a quasi-de Sitter solution for cosmic evolution. To ensure consistency with the standard cosmological model, we impose a matching condition with the $Λ$CDM model at the end of the inflationary phase. Furthermore, to address the problem of the absence of matter after inflation, we consider a radiation-type particle creation process that maintains an approximately constant energy density. We test our theoretical model against background observational data, specifically Pantheon+ calibrated with SH0ES and DESI calibrated with BBN. We asses its viability and discuss implications for alleviating the Hubble constant tension.
title Investigating $f(R)$-Inflation: background evolution and constraints
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2507.13890