Can BBH Merger GW Data Constrain Corrections to Bekenstein-Hawking Entropy ?

Abstract: We examine possible additive corrections to the Bekenstein-Hawking (BH) entropy of black holes due to very general classical and quantal modifications of general relativity. In general, black hole entropy is subject to the Generalized Second Law of Thermodynamics. For the case of binary black hole coalescence, the difference in corrections to the inspiral and remnant black hole entropies is shown, within this law, to be bounded by the difference in the corresponding BH entropies. This latter difference has been measured by several groups attempting to validate Hawking's Area Theorem on black hole horizons, by analyzing gravitational wave data from possible binary black hole mergers. The former difference - that between corrections to remnant and inspiral black hole entropies beyond the BH entropy, is thus constrained by a bound measured from observational data. We examine the implications of this constraint for general binary black hole coalesence. If calculated entropy corrections follow the essential pattern of BH entropies dictated by the Hawking Area Theorem, consistency with the observational bound is shown to be guaranteed. If they do not, these corrections are then nontrivially constrained by the observational bound.