Isolation of gravitational waves from displacement noise and utility of a time-delay device

Abstract

Interferometers with kilometer-scale arms have been built for gravitational-wave detections on the ground; ones with much longer arms are being planned for space-based detection. One fundamental motivation for long baseline interferometry is from displacement noise. In general, the longer the arm length L, the larger the motion the gravitational-wave induces on the test masses, until L becomes comparable to the gravitational wavelength. Recently, schemes have been invented, in which displacement noises can be evaded by employing differences between the influence of test-mass motions and that of gravitational waves on light propagation. However, in these schemes, such differences only becomes significant when L approaches the gravitational wavelength, and shot-noise limited sensitivity becomes worse than that of conventional configurations by a factor of at least (f L/c)^(-2), for f<c/L. Such a factor, although can be overcome theoretically by employing high optical powers, makes these schemes quite impractical. In this paper, we explore the use of time delay in displacement-noise-free interferometers, which can improve their shot-noise-limited sensitivity at low frequencies, to a factor of (f L/c)^(-1) of the shot-noise-limited sensitivity of conventional configurations.

10 pages, 12 figures, a proceeding for the Spanish Relativity Meeting ERE 2006

References in corpus (4)

• The Response of Test Masses to Gravitational Waves in the Coordinates of a Local Observer
• Interferometers for Displacement-Noise-Free Gravitational-Wave Detection
• A comparison between matter wave and light wave interferometers for the detection of gravitational waves
• Displacement- and Timing-Noise Free Gravitational-Wave Detection

Cited by in corpus (2)

• Octahedron configuration for a displacement noise-cancelling gravitational wave detector in space
• Resonant speed meter for gravitational wave detection