# Quasinormal mode oscillations in an analogue black hole experiment

## TL;DR

This paper reports an experiment observing quasinormal mode oscillations in a hydrodynamical vortex flow, supporting the idea that black hole-like oscillations can be studied in analogue gravity systems.

## Contribution

It provides experimental evidence of quasinormal ringing in an analogue black hole setup, highlighting the universality of these oscillations across different physical systems.

## Key findings

- Observation of quasinormal mode oscillations in a hydrodynamical vortex
- Evidence supporting the ubiquity of quasinormal ringing in analogue black holes
- Demonstration of black hole relaxation processes in laboratory conditions

## Abstract

The late stages of the relaxation process of a black hole are expected to depend only on its mass and angular momentum and not on the details of its formation process. Inspired by recent analogue gravity experiments, which demonstrate that certain black hole processes take place in gravitational and hydrodynamical systems alike, we conduct an experiment to search for quasinormal mode oscillations of the free surface of a hydrodynamical vortex flow. Our results demonstrate the occurrence and hint at the ubiquity of quasinormal ringing in nonequilibrium analog black hole experiments.