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Rotational superradiant scattering in a vortex flow

Torres, Theo; Patrick, Sam; Coutant, Antonin; Richartz, Mauricio; Tedford, Edmund W.; Weinfurtner, Silke


Theo Torres

Sam Patrick

Antonin Coutant

Mauricio Richartz

Edmund W. Tedford

Professor of Mathematicaland Experimental Physics


When an incident wave scatters off of an obstacle, it is partially reflected and partially transmitted. In theory, if the obstacle is rotating, waves can be amplified in the process, extracting energy from the scatterer. Here we describe in detail the first laboratory detection of this phenomenon, known as superradiance 1, 2, 3, 4. We observed that waves propagating on the surface of water can be amplified after being scattered by a draining vortex. The maximum amplification measured was 14% ± 8%, obtained for 3.70 Hz waves, in a 6.25-cm-deep fluid, consistent with the superradiant scattering caused by rapid rotation. We expect our experimental findings to be relevant to black-hole physics, since shallow water waves scattering on a draining fluid constitute an analogue of a black hole 5, 6, 7, 8, 9, 10, as well as to hydrodynamics, due to the close relation to over-reflection instabilities 11, 12, 13.


Torres, T., Patrick, S., Coutant, A., Richartz, M., Tedford, E. . W., & Weinfurtner, S. (2017). Rotational superradiant scattering in a vortex flow. Nature Physics, 13,

Journal Article Type Article
Acceptance Date Apr 25, 2017
Online Publication Date Jun 12, 2017
Publication Date Sep 1, 2017
Deposit Date Jun 29, 2017
Publicly Available Date Jun 29, 2017
Journal Nature Physics
Print ISSN 1745-2473
Electronic ISSN 1745-2481
Publisher Nature Publishing Group
Peer Reviewed Peer Reviewed
Volume 13
Keywords Fluid dynamics, High-energy astrophysics
Public URL
Publisher URL
Copyright Statement Copyright information regarding this work can be found at the following address:


experimentalsuperradiance_after_acceptance_v3.pdf (1.9 Mb)

Copyright Statement
Copyright information regarding this work can be found at the following address:

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