Viability of Arctan Model of f(R) Gravity for Late-time Cosmology

TL;DR

This paper evaluates a specific $f(R)$ gravity model's suitability for late-time cosmology, finding it incompatible due to fifth-force constraints and curvature singularities.

Contribution

It critically assesses the viability of a proposed $f(R)$ model for explaining cosmic acceleration, highlighting key physical constraints.

Findings

Violates fifth-force constraints

Suffers from curvature singularities in collapsing objects

Not suitable for late-time cosmology

Abstract

$f(R)$ modifications of Einstein's gravity is an interesting possibility to explain the late time acceleration of the Universe. In this work we explore the cosmological viability of one such $f(R)$ modification proposed in (Kruglov:2013). We show that the model violates fifth-force constraints. The model is also plagued with the issue of curvature singularity in a spherically collapsing object, where the effective scalar field reaches to the point of diverging scalar curvature.