Bekenstein-Hod Universal Bound on Information Emission Rate Is Obeyed by LIGO-Virgo Binary Black Hole Remnants

Causality and the generalized laws of black hole thermodynamics imply a bound, known as the $\mathit{\text{Bekenstein–Hod}}\mathit{\text{universal}}\mathit{\text{bound}}$, on the information emission rate of a perturbed system. Using a time-domain ringdown analysis, we investigate whether remnant black holes produced by the coalescences observed by Advanced LIGO and Advanced Virgo obey this bound. We find that the bound is verified by the astrophysical black hole population with $94\mathrm{\%}$ probability, providing a first confirmation of the Bekenstein–Hod bound from black hole systems.