From the gates of the abyss: Frequency- and polarization-dependent lensing of gravitational waves in strong gravitational fields

Author(s)
Marius Adrian Oancea, Richard Stiskalek, Miguel Zumalacarregui
Abstract

The propagation of gravitational waves can be described in terms of null geodesics by using the geometrical optics approximation. However, at large but finite frequencies the propagation is affected by the spin-orbit coupling corrections to geometrical optics, known as the gravitational spin Hall effect. Consequently, gravitational waves follow slightly different frequency- and polarization-dependent trajectories, leading to dispersive and birefringent phenomena. We study the potential for detecting the gravitational spin Hall effect in hierarchical triple black hole systems, consisting of an emitting binary orbiting a more massive body acting as a gravitational lens. We calculate the difference in time of arrival with respect to the geodesic propagation and find that it follows a simple power-law dependence on frequency with a fixed exponent. We calculate the gravitational spin Hall-corrected waveform and its mismatch with respect to the original waveform. The waveform carries a measurable imprint of the strong gravitational field if the source, lens, and observer are sufficiently aligned, or for generic observers if the source is close enough to the lens. We present constraints on dispersive time delays from GWTC-3, translated from limits on Lorentz invariance violation. Finally, we address the sensitivity of current and future ground detectors to dispersive lensing. Our results demonstrate that the gravitational spin Hall effect can be detected, providing a novel probe of general relativity and the environments of compact binary systems.

Organisation(s)
Gravitational Physics
External organisation(s)
University of Oxford, Max-Planck-Institut für Gravitationsphysik (Albert Einstein Institut), Ludwig-Maximilians-Universität München
Volume
arXiv:2209.06459
Pages
arXiv:2209.06459
DOI
https://doi.org/10.48550/arXiv.2209.06459
Publication date
09-2022
Austrian Fields of Science 2012
103028 Theory of relativity, 103004 Astrophysics
Portal url
https://ucris.univie.ac.at/portal/en/publications/from-the-gates-of-the-abyss-frequency-and-polarizationdependent-lensing-of-gravitational-waves-in-strong-gravitational-fields(393d3e69-ff22-4ff5-8f7c-efec454078c3).html