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Internal structure of vortices in superfluids and implications for quantum turbulence

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Dense Bose superfluids, as HeII, differ from dilute ones by the existence of a roton minimum in their excitation spectrum. It is known that this roton minimum is qualitatively responsible for density oscillations close to any singularity, such as vortex cores, or close to solid boundaries. We show that the period of these oscillations, and their exponential decrease with the distance to the singularity, are fully determined by the depth and the width of the roton minimum. We then study, based on a numerical simulation of the Gross-Pitaeviskii equation with a non-local interaction term, the implication of these oscillations on the vortex reconnection process, and quantify the amount of energy transfered from vortices to the background flow.

Author(s):

Sophie Villerot    
Laboratoire de Physique de l'ENS Lyon, CNRS, Universite de Lyon, 46 allee d'Italie, 69007 Lyon, France
France

Bernard Castaing    
Laboratoire de Physique de l'ENS Lyon, CNRS, Universite de Lyon, 46 allee d'Italie, 69007 Lyon, France
France

Laurent Chevillard    
Laboratoire de Physique de l'ENS Lyon, CNRS, Universite de Lyon, 46 allee d'Italie, 69007 Lyon, France
France