Chameleon perfect scalar field as a geometric correction in $f(R)$ gravity

TL;DR

This paper derives an $f(R)$ gravity model incorporating a chameleon scalar field, which can mimic dark sector components and satisfy cosmological constraints from inflation to late times.

Contribution

It introduces an analytical $f(R)$ model with a perfect scalar chameleon field, linking geometric corrections to dark sector phenomena and cosmological constraints.

Findings

The $f(R)$ model describes a perfect scalar field with chameleon mechanism.

The model can explain dark sector phenomena as geometric fluid.

It satisfies BBN constraints during inflation and late times.

Abstract

In this work, we derive the analytical form for a $f(R)$ model that describes a perfect scalar field $\phi$ by assuming the existence of a chameleon mechanism. Based on four statements, at the background and perturbative level, it is possible to relate the extra terms from this theory as a geometrical perfect fluid term, whose has been expressed as possible candidates to explain the nature of the dark sector, and possibly, in the case of a perfect scalar chameleon during inflation, satisfy the big bang nucleosynthesis (BBN) constraints until late times.