Rotating analogue black holes: Quasinormal modes and tails, superresonance, and sonic bombs and plants in the draining bathtub acoustic hole

TL;DR

This paper explores the properties of rotating acoustic black holes, including quasinormal modes, superresonance, and instabilities, demonstrating potential applications in energy amplification and sound wave manipulation.

Contribution

It advances understanding of rotating acoustic black holes by analyzing their quasinormal modes, superresonance effects, and instabilities, with implications for energy storage and sonic devices.

Findings

Identification of quasinormal modes and tails in draining bathtub acoustic holes

Observation of superresonance phenomena in rotating acoustic black holes

Analysis of instabilities leading to energy amplification in reflective setups

Abstract

The analogy between sound wave propagation and light waves led to the study of acoustic holes, the acoustic analogues of black holes. Many black hole features have their counterparts in acoustic holes. The Kerr metric, the rotating metric for black holes in general relativity, has as analogue the draining bathtub metric, a metric for a rotating acoustic hole. Here we report on the progress that has been made in the understanding of features, such as quasinormal modes and tails, superresonance, and instabilities when the hole is surrounded by a reflected mirror, in the draining bathtub metric. Given then the right settings one can build up from these instabilities an apparatus that stores energy in the form of amplified sound waves. This can be put to wicked purposes as in a bomb, or to good profit as in a sonic plant.