Fast radio bursts and the stochastic lifetime of black holes in quantum gravity

Abstract

Nonperturbative quantum gravity effects might allow a black-to-white hole transition. We revisit this increasingly popular hypothesis by taking into account the fundamentally random nature of the bouncing time. We show that if the primordial mass spectrum of black holes is highly peaked, the expected signal can in fact match the wavelength of the observed fast radio bursts. On the other hand, if the primordial mass spectrum is wide and smooth, clear predictions are suggested and the sensitivity to the shape of the spectrum is studied.

A Status Report on the Phenomenology of Black Holes in Loop Quantum Gravity: Evaporation, Tunneling to White Holes, Dark Matter and Gravitational Waves

“…This apparent discrepancy has been addressed and solved in [77]. The key idea lies in the fact that if the black-to-white hole transition is to be understood as a tunneling process, the lifetime of a BH should be considered as a random variable.…”

“…Importantly, is was also shown in [77] that even if the mass spectrum is wide, it could still be possible to explain FRBs. It could be that most bouncing BHs lead to a signal of wavelength 0.02 cm and that only the tail (whose existence is due to the probabilistic nature of the lifetime) of the distribution is actually detected by radio-telescopes.…”

“…Electromagnetic flux emitted by bouncing BHs for a mean mass M0 of (from right to left) Mt H , 10Mt H , 100Mt H , and 1000Mt H , normalized such that the total mass going into PBHs is the same. From[77].…”

Fundamental physics with the Square Kilometre Array

“…Various signals can be expected (Barrau et al 2016(Barrau et al , 2018a: (1) a highenergy signal determined by the temperature of the photons emitted, (2) a signal determined by the size of the hole exploding, (3) a signal in the radio due to the possible presence of magnetic fields around the exploding hole, and (4) the emission in GWs. The peak of signal (2) falls at millimetre wavelengths; however, the full distribution of events is accessible to SKA1-Mid (Barrau et al 2018b). Interestingly, the signal presents a peculiar wavelength-distance relation (Barrau et al 2014), which allows it to be discriminated from other astrophysical sources, either via direct detection, or via the resulting background radiation (Barrau et al 2016) that SKA IM may detect, especially with the improved sensitivity of SKA2-Mid.…”

Quasinormal modes of black holes in a toy-model for cumulative quantum gravity

“…If one estimates the intensity of quantum gravitational effects through the ratio of Planck length over the curvature scale, the result is vanishingly small for stellar or supermassive BHs. This vision however disregards possible cumulative effects (also considered in [29][30][31][32]). Dimensional arguments lead to the conclusion that the "quantumness" of spacetime, integrated over a proper time τ , might be given by q = l P R τ .…”