Acoustic white holes in flowing atomic Bose-Einstein condensates

Year: 2011

Authors: Mayoral C., Recati A., Fabbri A., Parentani R., Balbinot R., Carusotto I.

Autors Affiliation: Departamento de Física Teórica and IFIC, Universidad de Valencia-CSIC, C Dr Moliner 50, 46100 Burjassot, Spain; INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, via Sommarive 14, I-38123 Povo, Italy; APC (Astroparticules et Cosmologie), 10 rue A Domon et L Duquet, 75205 Paris Cedex 13, France; Laboratoire de Physique Théorique, CNRS UMR 8627, Bât. 210, Université Paris-Sud 11, 91405 Orsay Cedex, France; Dipartimento di Fisica dell\’Università di Bologna and INFN sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy

Abstract: We study acoustic white holes in a steadily flowing atomic Bose-Einstein condensate. A white hole configuration is obtained when the flow velocity goes from a super-sonic value in the upstream region to a sub-sonic one in the downstream region. The scattering of phonon wavepackets on a white hole horizon is numerically studied in terms of the Gross-Pitaevskii equation of mean-field theory: dynamical stability of the acoustic white hole is found, as well as a signature of a nonlinear back-action of the incident phonon wavepacket onto the horizon. The correlation pattern of density fluctuations is numerically studied by means of the truncated-Wigner method, which includes quantum fluctuations. Signatures of the white hole radiation of correlated phonon pairs by the horizon are characterized; analogies and differences with Hawking radiation from acoustic black holes are discussed. In particular, a short wavelength feature is identified in the density correlation function, whose amplitude steadily grows in time since the formation of the horizon. The numerical observations are quantitatively interpreted by means of an analytical Bogoliubov theory of quantum fluctuations for a white hole configuration within the step-like horizon approximation.

Journal/Review: NEW JOURNAL OF PHYSICS

Volume: 13      Pages from: 25007-1  to: 25007-29

More Information: We are indebted to N Pavloff and M Rinaldi for stimulating discussions. AF thanks the Generalitat Valenciana for financial support. AF and CM are supported in part by MICINN grant no. FIS2008-06078-C03-02. CM is indebted to the Spanish MEC for an FPU fellowship. CM thanks the Universita di Bologna and the BEC Center in Trento for their charming hospitality during the elaboration of this work.
KeyWords: Bioelectric phenomena; Bose-Einstein condensation; Mean field theory; Nonlinear equations; Phonons; Quantum electronics; Stability; Statistical mechanics; Steam condensers; Wave packets
DOI: 10.1088/1367-2630/13/2/025007

Citations: 44
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