Response of Interferometric Detectors to Scalar Gravitational Waves

TL;DR

This paper analyzes how different interferometric gravitational wave detectors respond to scalar gravitational waves, revealing that sensitivity patterns depend on wave length and detector type, with implications for detection strategies.

Contribution

It provides a detailed analysis of the frequency response and sensitivity patterns of various interferometers to scalar gravitational waves, highlighting dependence on wave length and detector configuration.

Findings

Sensitivity patterns depend on wave length for simple Michelson detectors.

Delay-Line and Fabry-Perot detectors show weak dependence on wave length.

Results align with previous findings by Maggiore and Nicolis.

Abstract

We rigorously analyze the frequency response functions and antenna sensitivity patterns of three types of interferometric detectors to scalar mode of gravitational waves which is predicted to exist in the scalar-tensor theory of gravity. By a straightforward treatment, we show that the antenna sensitivity pattern of the simple Michelson interferometric detector depends strongly on the wave length $\lambda_{\rm SGW}$ of the scalar mode of gravitational waves if $\lambda_{\rm SGW}$ is comparable to the arm length of the interferometric detector. For the Delay-Line and Fabry-Perot interferometric detectors with arm length much shorter than $\lambda_{\rm SGW}$, however, the antenna sensitivity patterns depend weakly on $\lambda_{\rm SGW}$ even though $\lambda_{\rm SGW}$ is comparable to the effective path length of those interferometers. This agrees with the result obtained by Maggiore and Nicolis.