Singularity phenomena in viable f(R) gravity

TL;DR

This paper investigates curvature singularities in viable f(R) gravity models under dense conditions and proposes adding an R^2 term to eliminate these singularities, discussing implications for gravitational waves.

Contribution

It demonstrates that adding an R^2 term can remove singularities in f(R) gravity and explores related cosmological consequences, especially for gravitational wave sources.

Findings

Adding R^2 term eliminates singularities in dense environments.

The scalar mode of gravitational waves is affected by the modified gravity.

Cosmological implications include potential changes in gravitational wave signals.

Abstract

The curvature singularity in viable f(R) gravity models is examined when the background density is dense. This singularity could be eliminated by adding the $R^{2}$ term in the Lagrangian. Some of cosmological consequences, in particular the source for the scalar mode of gravitational waves, are discussed.