Quasinormal modes and classical wave propagation in analogue black holes

TL;DR

This paper explores sound wave behavior in analogue black holes, focusing on quasinormal modes, superradiance, and wave tails in rotating and non-rotating acoustic black hole models, providing insights into black hole physics through laboratory analogues.

Contribution

It presents detailed calculations of quasinormal modes, superradiant amplification, and instability timescales in acoustic black hole analogues, extending understanding of wave dynamics in these systems.

Findings

Computed quasinormal mode frequencies for rotating acoustic black holes

Demonstrated superradiant wave amplification and instability in the acoustic black hole bomb

Analyzed late-time power-law tails in wave propagation

Abstract

Many properties of black holes can be studied using acoustic analogues in the laboratory through the propagation of sound waves. We investigate in detail sound wave propagation in a rotating acoustic (2+1)-dimensional black hole, which corresponds to the ``draining bathtub'' fluid flow. We compute the quasinormal mode frequencies of this system and discuss late-time power-law tails. Due to the presence of an ergoregion, waves in a rotating acoustic black hole can be superradiantly amplified. We compute superradiant reflection coefficients and instability timescales for the acoustic black hole bomb, the equivalent of the Press-Teukolsky black hole bomb. Finally we discuss quasinormal modes and late-time tails in a non-rotating canonical acoustic black hole, corresponding to an incompressible, spherically symmetric (3+1)-dimensional fluid flow.