Cosmic History of Chameleonic Dark Matter in $F(R)$ Gravity

TL;DR

This paper explores how $F(R)$ gravity's scalaron can serve as dark matter throughout cosmic history and discusses its potential to solve the coincidence problem using the chameleon mechanism.

Contribution

It introduces a novel scenario where the scalaron in $F(R)$ gravity acts as dark matter and addresses the coincidence problem.

Findings

Scalaron can function as dark matter in the universe.

$F(R)$ gravity may resolve the coincidence problem.

Chameleon mechanism enables scalaron to adapt to cosmic environments.

Abstract

We study the cosmic history of the scalaron in $F(R)$ gravity with constructing the time evolution of the cosmic environment and discuss the chameleonic dark matter based on the chameleon mechanism in the early and current Universe. We then find that the scalaron can be a dark matter. We also propose an interesting possibility that the $F(R)$ gravity can address the coincidence problem.