f(R) Cosmology, analytical inversion method
Issued Date
2026-01-01
Resource Type
ISSN
05503213
Scopus ID
2-s2.0-105023496790
Journal Title
Nuclear Physics B
Volume
1022
Rights Holder(s)
SCOPUS
Bibliographic Citation
Nuclear Physics B Vol.1022 (2026)
Suggested Citation
Senjaya D. f(R) Cosmology, analytical inversion method. Nuclear Physics B Vol.1022 (2026). doi:10.1016/j.nuclphysb.2025.117214 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/114797
Title
f(R) Cosmology, analytical inversion method
Author(s)
Author's Affiliation
Corresponding Author(s)
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Abstract
Inflation, the rapid expansion of spacetime in the early universe, provides an elegant resolution to several fundamental cosmological problems. Among various theoretical approaches, f ( R ) gravity offers a minimal yet powerful extension of General Relativity capable of generating inflationary dynamics. In this work, we aim to provide a detailed and systematic derivation of a bottom-up analytical reconstruction method for f ( R ) gravity, given the number of e-folds and the scalar power spectrum under the slow-roll approximation. Through explicit calculation, we demonstrate that an exponential dependence of the scalar spectrum on the e-fold number leads to the theory f(R)=R+R<sup>2</sup>8κV<inf>0</inf>[32κln(RR0)−ϕ0]<sup>2(α−1)</sup>, while a linear dependence yields, f(R)=R+A<inf>0</inf>R<sup>2</sup>(RR0)<sup><sup><sup>3α</sup><sup>2κ</sup></sup></sup>. Our analysis provides a transparent derivation of these functional forms and highlights how specific choices of the scalar spectrum naturally reconstruct distinct inflationary f ( R ) models.