Amplification of waves from a rotating body

Cromb, M. , Gibson, G. M. , Toninelli, E. , Padgett, M. J. , Wright, E. M. and Faccio, D. (2020) Amplification of waves from a rotating body. Nature Physics, (doi: 10.1038/s41567-020-0944-3) (Early Online Publication)

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Abstract

In 1971, Zel’dovich predicted that quantum fluctuations and classical waves reflected from a rotating absorbing cylinder will gain energy and be amplified. This concept, which is a key step towards the understanding that black holes may amplify quantum fluctuations, has not been verified experimentally owing to the challenging experimental requirement that the cylinder rotation rate must be larger than the incoming wave frequency. Here, we demonstrate experimentally that these conditions can be satisfied with acoustic waves. We show that low-frequency acoustic modes with orbital angular momentum are transmitted through an absorbing rotating disk and amplified by up to 30% or more when the disk rotation rate satisfies the Zel’dovich condition. These experiments address an outstanding problem in fundamental physics and have implications for future research into the extraction of energy from rotating systems.

Item Type:Articles
Status:Early Online Publication
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gibson, Dr Graham and Faccio, Professor Daniele and Toninelli, Ermes and Padgett, Professor Miles and Cromb, Mx Marion
Authors: Cromb, M., Gibson, G. M., Toninelli, E., Padgett, M. J., Wright, E. M., and Faccio, D.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Nature Physics
Publisher:Nature Research
ISSN:1745-2473
ISSN (Online):1745-2481
Published Online:22 June 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Nature Physics 2020
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
303021Black Hole Superradiance in Rotating Fluids (SURF)Daniele FaccioEngineering and Physical Sciences Research Council (EPSRC)EP/P006078/2P&S - Physics & Astronomy
303359PhoQusDaniele FaccioEuropean Commission (EC)820392P&S - Physics & Astronomy