$f(R)$ gravity constrained by PPN parameters and stochastic background of gravitational waves

TL;DR

This paper evaluates seven viable $f(R)$ gravity models against Solar System tests and gravitational wave background constraints, aiming to identify models consistent with local and cosmological observations without a cosmological constant.

Contribution

It demonstrates that these models satisfy both Solar System tests and gravitational wave bounds, narrowing down viable $f(R)$ theories for explaining cosmic acceleration.

Findings

All models pass Solar System tests.

Models are consistent with stochastic gravitational wave bounds.

Parameter spaces are constrained by combined local and cosmological tests.

Abstract

We analyze seven different viable $f(R)$-gravities towards the Solar System tests and stochastic gravitational waves background. The aim is to achieve experimental bounds for the theory at local and cosmological scales in order to select models capable of addressing the accelerating cosmological expansion without cosmological constant but evading the weak field constraints. Beside large scale structure and galactic dynamics, these bounds can be considered complimentary in order to select self-consistent theories of gravity working at the infrared limit. It is demonstrated that seven viable $f(R)$-gravities under consideration not only satisfy the local tests, but additionally, pass the above PPN-and stochastic gravitational waves bounds for large classes of parameters.