Generic f(R) theories and classicality of their scalarons

TL;DR

This paper investigates the quantum stability of scalarons in generic $f(R)$ gravity theories, revealing that environmental density affects scalaron mass and proposing quadratic corrections to ensure stability.

Contribution

It demonstrates that scalaron mass increases rapidly with local density in generic $f(R)$ models, violating quantum bounds, and shows quadratic curvature corrections can stabilize the theory.

Findings

Scalaron mass grows faster than quantum corrections in generic $f(R)$ models.

Quantum bound on the chameleon mass can be violated without stabilization.

Quadratic curvature corrections stabilize the scalaron in $f(R)$ theories.

Abstract

We study quantum stability bound on the mass of scalaron in generic theories of $f(R)$ gravity. We show that in these scenarios, the scalaron mass increases faster with local density of the environment than one loop quantum correction to it thereby leading to violation of quantum bound on the chameleon mass. The introduction of quadratic curvature corrections in the action are shown to stabilize the model.