Eur. Phys. J. C (2020) 80: 1032
https://doi.org/10.1140/epjc/s10052-020-08628-x

Regular Article – Theoretical Physics

Tests of CPT invariance in gravitational waves with LIGO-Virgo catalog GWTC-1

¹ Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, People’s Republic of China
² School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, People’s Republic of China
³ Department of Astronomy, Beijing Normal University, 100875, Beijing, People’s Republic of China

^b zhaozc@bnu.edu.cn

Received: 25 August 2020
Accepted: 31 October 2020
Published online: 8 November 2020

Abstract

A discovery of gravitational waves from binary black holes raises a possibility that measurements of them can provide strict tests of CPT invariance in gravitational waves. When CPT violation exists, if any, gravitational waves with different circular polarizations could gain a slight difference in propagating speeds. Hence, the birefringence of gravitational waves is induced and there should be a rotation of plus and cross modes. For CPT-violating dispersion relation ${\omega }^2=k^2$$\pm 2\zeta k^3$, where a sign $\pm$ denotes different circular polarizations, we find no substantial deviations from CPT invariance in gravitational waves by analyzing a compilation of ten signals of binary black holes in the LIGO-Virgo catalog GWTC-1. We obtain a strict constraint on the CPT-violating parameter, i.e., $\zeta =0.{14}_{-0.31}^{+0.22}\times {10}^{-15}\text{m}$, which is around two orders of magnitude better than the existing one. Therefore, this study stands for the up-to-date strictest tests of CPT invariance in gravitational waves.