Quantum black hole spectroscopy: probing the quantum nature of the black hole area using LIGO–Virgo ringdown detections

Abstract

We present a thorough observational investigation of the heuristic quantised ringdown model presented by Foit and Kleban (2019 Class. Quantum Grav. 36 035006). This model is based on the Bekenstein–Mukhanov conjecture, stating that the area of a black hole (BH) horizon is an integer multiple of the Planck area l P 2 multiplied by a phenomenological constant, α, which can be viewed as an additional BH intrinsic parameter. Our approach is based on a time-domain analysis of the gravitational wave (GW) signals produced by the ringdown phase of binary BH mergers detected by the LIGO and Virgo collaboration. Employing a full Bayesian formalism and taking into account the complete correlation structure among the BH parameters, we show that the value of α cannot be constrained using only GW150914, in contrast to what was suggested by Foit and Kleban (2019 Class. Quantum Grav. 36 035006). We proceed to repeat the same analysis on the new GW events detected by the LIGO and Virgo Collaboration up to 1 October 2019, obtaining a combined-event measure equal to α = 15 . 6 − 13.3 + 20.5 and a combined log odds ratio of 0.1 ± 0.6, implying that current data are not informative enough to favor or discard this model against general relativity. We then show that using a population of O ( 20 ) GW150914-like simulated events—detected by the current infrastructure of ground-based detectors at their design sensitivity—it is possible to confidently falsify the quantised model or prove its validity, in which case probing α at the few % level. Finally we classify the stealth biases that may show up in a population study.

Destabilizing the Fundamental Mode of Black Holes: The Elephant and the Flea

“…One of the tools to test the Kerr geometry is BH spectroscopy [24-26], now a thriving field [27][28][29][30][31][32][33][34]. If a compact binary merger leads to the formation of a rotating BH, as predicted in GR, the spacetime should asymptote to the Kerr metric through a relaxation process during which it can be described as a perturbation of the Kerr metric.…”

“…The simplicity of BHs (whether isolated or in binaries) implies that they are ideal laboratories to probe the limitations of GR, as long as environmental effects or astrophysical uncertainties can be ignored. In this Letter we ask an important question: is it really possible to ignore environmental effects?One of the tools to test the Kerr geometry is BH spectroscopy [24-26], now a thriving field [27][28][29][30][31][32][33][34]. If a compact binary merger leads to the formation of a rotating BH, as predicted in GR, the spacetime should asymptote to the Kerr metric through a relaxation process during which it can be described as a perturbation of the Kerr metric.…”

Constraints on Kerr-Newman black holes from merger-ringdown gravitational-wave observations

“…Moreover, it has been employed to explore possible signatures [86][87][88] of the area quantisation on the BH ringdown emission in Ref. [89] and to obtain bounds [84] on a possible new physics length scale entering QNM spectra, in a linearized perturbative scheme [90].…”

Probing horizon scale quantum effects with Love

“…One of the very intriguing questions in fundamental physics is how gravity behaves in the quantum regime. Since GWs bring information from the very close vicinity of BHs, it is expected that GWs may shed some light on this mystery [35][36][37][38][39][40][41]. The idea behind such expectations follows from the fact that the Planck scale physics may affect the tidal Love numbers of the compact objects [11,12].…”