Loop-corrected scalar potentials and late-time acceleration in f(R) gravity

Title

Loop-corrected scalar potentials and late-time acceleration in f(R) gravity

Creator

Pradosh Keshav, M.V.; Kenath, Arun

Description

We construct an analytic f(R) gravity model that unifies early-time inflation with late-time cosmic acceleration within a single covariant framework. At high curvature, the model reproduces a Starobinsky-like inflationary plateau, while at low curvature it asymptotes to a stable dark energy-dominated phase. In the scalar-tensor representation, this construction yields a hilltop-type potential in the Jordan frame, which maps to an exponential potential in the Einstein frame. To account for radiative effects, we introduce a logarithmic correction to the Einstein-frame potential inspired by one-loop effective field theory, producing a late-time flattening without requiring fine-tuning. The resulting scalaron dynamics reduce the effective mass to O(H0), inducing a thawing regime that deviates from a cosmological constant at the sub-percent levels. A joint background likelihood analysis using Pantheon+SH0ES and BAO+CC datasets (within the CPL parametrization) yields H0=73.40.6 km/s/Mpc and ?m=0.2530.007, consistent with local expansion rate measurements. The best-fit scalar field parameters are ?0?0.027MPl and ??0.010MPl, corresponding to a present-day dark energy equation of state w0?-0.985. While compatible with ?CDM within current observational bounds, the model satisfies GR recovery at low curvature and exhibits attractor-like behavior, thereby minimizing sensitivity to initial conditions. The Author(s) 2025.

Source

European Physical Journal C;Volume;85;Issue;9;Article No.;990;

Date

01-01-2025

Publisher

Springer Nature

Coverage

Pradosh Keshav M.V., Department of Physics and Electronics, Christ University, Bangalore, 560029, India; Kenath A., Department of Physics and Electronics, Christ University, Bangalore, 560029, India

Rights

All Open Access; Gold Open Access; Green Open Access

Relation

ISSN: 14346044;

Format

online

Language

English

Type

Article

Identifier

https://doi.org/10.1140/epjc/s10052-025-14737-2

https://www.scopus.com/pages/publications/105016463571?origin=resultslist