One can find dense, dark understanding in a bathtub, if one is a physicist. This new study provides an example:
“Black Hole Quasibound States from a Draining Bathtub Vortex Flow,” Sam Patrick, Antonin Coutant, Maurício Richartz, and Silke Weinfurtner, Physical Review Letters, vol. 121, nos. 6-10, 2018, 061101. The authors, at the University of Nottingham, UK, and Universidade Federal do ABC (UFABC), Brazil, report:
“We present a hydrodynamic analog of a rotating black hole that illustrates how the presence of extra structure affects the quasinormal mode spectrum. The analogy is obtained by considering wave scattering on a draining bathtub vortex flow. We show that due to vorticity of the background flow, the resulting field theory corresponds to a scalar field on an effective curved spacetime which acquires a local mass in the vortex core. The obtained quasinormal mode spectrum exhibits long-lived trapped modes, commonly known as quasibound states.”
There exists a video, prepared by the team:
