QFS2016 Book of Abstracts

Abstracts

O4.10 Evolution of a superfluid vortex filament tangle driven by the Gross-Pitaevskii equation Villois Alberto(1), Proment Davide(1), Krstulovic Giorgio(2) 1) University of East Anglia, School of Mathematics, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom 2) Universit´e de la Cˆote d’Azur, CNRS, Observatoire de la Cˆote d’Azur, Laboratoire J.L. Lagrange, UMR7293, B.P. 4229, 06304 Nice Cedex 4, France We study the evolution of a vortex filament tangle driven by the Gross-Pitaevskii equation using a recently developed vortex-tracking algorithm. We observe the Vinen’s decay law for the vortex line density with a coefficient that is in quantitative agreement with the values measured in Helium II. We investigate the properties of the tangle, showing that linked rings may appear and that local curvature and torsion distributions exhibit large fluctuations and self-similar dynamics. We obtain the temporal evolution of the Kelvin wave spectrum providing evidence of the development of a weak-wave turbulence cascade. Ongoing investigations on reconnections may also be presented. (arXiv:1605.00567) J.-P. Kaikkonen, A. Savin, A. Laitinen, I. Todoshchenko, and P.J. Hakonen Low Temperature Laboratory, Department of Applied Physics, Aalto University, 00076 AALTO, Finland Suspended graphene and carbon nanotube devices are among the most precise mass, force and charge sensors. We are utilizing these ultrasensitive devices in investigations of atomic layers and bulk superfluid phases of 3 He and 4 He. In our first experiments we have investigated thin superfluid 4 He layers on top of graphene resonators. Shifts of resonance frequency as well as changes in the resonance structure are found. For reference, we have studied fully superfluid-immersed graphene resonators. In these experiments, we have also investigated dynamic behavior of two gold MEMS resonators coupled non-linearly via graphene. Internal resonances in this coupled system are observed. O4.11 Graphene resonators in studies of quantum fluids

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