Scalar perturbations and stability of a loop quantum corrected Kruskal black hole

We investigate the massless scalar field perturbations of a new loop quantum gravity motivated regular black hole proposed by Ashtekar et al. in [Quantum Transfiguration of Kruskal Black Holes, Phys. Rev. Lett. 121, 241301 (2018), Quantum extension of the kruskal space-time, Phys. Rev. D 98, 126003 (2018)]. The spacetime of this black hole is distinguished by its asymptotic properties: in Schwarzschild coordinates one of the metric functions diverges as r -> infinity even though the spacetime is asymptotically flat. We show that despite this unusual asymptotic behavior, the quasinormal mode potential is well defined everywhere when Schwarzschild coordinates arc used. We propose a useful approximate form of the metric, which allows us to produce quasinormal mode frequencies and ringdown waveforms to high accuracy with manageable computation times. Our results indicate that this black hole model is stable against massless scalar field perturbations. We show that, compared to the Schwarzschild black hole, this black hole oscillates with higher frequency and less damping. We also observe a qualitative difference in the power-law tail of the ringdown waveform between this black hole model and the Schwarzschild black hole. This suggests the quantum corrections affect the behavior of the waves at large distances from the black hole.

Automated summary

The study investigates the massless scalar field perturbations of a regular black hole model proposed by Ashtekar et al. based on loop quantum gravity, finding that the model is stable against such perturbations. In comparison to the Schwarzschild black hole, this new black hole model oscillates with higher frequency and less damping, exhibiting a qualitative difference in the power-law tail of the ringdown waveform. This suggests that quantum corrections impact the behavior of waves at large distances from the black hole.