Speaker
Description
Precessing black-hole mergers can produce an imbalance between right- and left-handed circularly polarized gravitational waves. According to the Cosmological Principle, such chiral emission should average out to zero across all binary mergers in our Universe in order to preserve mirror-reflection symmetry at very large scales. In this talk, I will show how gravitational-wave astronomy enables a unique, observer-independent test of this hypothesis. Specifically, I will introduce a new geometric observable within General Relativity, which is chiral and can be used to quantify the average net circular polarization emitted by an ensemble of binary black hole mergers detected by LIGO-Virgo. I will present current results and limitations, and discuss future prospects with upcoming detections and technical advancements. Notably, we find that this novel measure of circular polarization and the helicity of the remnant black hole are linearly correlated, drawing a conceptual parallel between this cosmological test and Wu’s experiment in particle physics.
Based on:
[1] J. Calderon-Bustillo, A. del Rio, N. Sanchis-Gual, K. Chandra, S. H. W. Leong, Phys. Rev. Lett. 134, 031402 (2025) [arXiv:2402.09861].
[2] S.H.W. Leong, A. Florido-Tomé, J. Calderon-Bustillo, A. del Rio, N. Sanchis-Gual, To appear in Phys. Rev. D (2025) [arXiv:2501.11663].
