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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Rotational superradiant scattering in a vortex flow

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Torres, Theo ; Patrick, Sam ; Coutant, Antonin ; Richartz, Mauricio ; Tedford, Edmund W. ; Weinfurtner, Silke
Total Authors: 6
Document type: Journal article
Source: Nature Physics; v. 13, n. 9, p. 833+, SEP 2017.
Web of Science Citations: 46

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(1-4). 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(5-10), as well as to hydrodynamics, due to the close relation to over-reflection instabilities(11-13). (AU)

FAPESP's process: 15/14077-0 - Superradiance in dissipative systems
Grantee:Maurício Richartz
Support Opportunities: Scholarships abroad - Research
FAPESP's process: 13/15748-0 - Analogue Models: superradiance and stability
Grantee:Maurício Richartz
Support Opportunities: Scholarships abroad - Research
FAPESP's process: 10/20123-1 - Analogue models of gravity
Grantee:Maurício Richartz
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 13/09357-9 - Physics and geometry of spacetime
Grantee:Alberto Vazquez Saa
Support Opportunities: Research Projects - Thematic Grants