Bogoliubov-Cerenkov radiation in a Bose-Einstein condensate flowing against an obstacle.
We study the density modulation that appears in a Bose-Einstein condensate flowing with supersonic velocity against an obstacle. The experimental density profiles observed at JILA are reproduced by a numerical integration of the Gross-Pitaevskii equation and then interpreted in terms of Cerenkov emission of Bogoliubov excitations by the defect. The phonon and the single-particle regions of the Bogoliubov spectrum are, respectively, responsible for a conical wave front and a fan-shaped series of precursors.
Carusotto
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CNR-BEC-INFM, Trento, I-38050 Povo, Italy.
Hu
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Collins
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Smerzi
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