Waveforms of compact binary inspiral gravitational radiation in screened modified gravity

TL;DR

This paper derives gravitational waveforms for inspiraling compact binaries within screened modified gravity, revealing additional polarization modes and providing a way to test these theories with future GW observations.

Contribution

It calculates GW waveforms including scalar polarizations in SMG and derives correction terms, enabling constraints on SMG theories from GW data.

Findings

Scalar polarizations $h_b$ and $h_L$ are linearly related.

Ground-based GW detectors can constrain SMG parameters.

Application to specific theories like chameleon and $f(R)$.

Abstract

Scalar-tensor gravity, with the screening mechanisms to avoid the severe constraints of the fifth force in the Solar System, can be described with a unified theoretical framework, the so-called screened modified gravity (SMG). Within this framework, in this paper we calculate the waveforms of gravitational-waves (GWs) emitted by inspiral compact binaries, which include four polarization modes, the plus $h_{+}$, cross $h_{\times}$, breathing $h_{b}$, and longitudinal $h_{L}$ modes. The scalar polarizations $h_b$ and $h_L$ are both caused by the scalar field of SMG, and satisfy a simple linear relation. With the stationary phase approximations, we obtain their Fourier transforms, and derive the correction terms in the amplitude, phase, and polarizations of GWs, relative to the corresponding results in general relativity. The corresponding parametrized post-Einsteinian parameters in the general SMG are also identified. Imposing the noise level of the ground-based Einstein Telescope, we find that GW detections from inspiral compact binaries composed of a neutron star and a black hole can place stringent constraints on the sensitivities of neutron stars, and the bound is applicable to any SMG theory. Finally, we apply these results to some specific theories of SMG, including chameleon, symmetron, dilaton and $f(R)$.