Publication Date:
2017-02-17
Description:
Author(s): Charles Bernando, Rico Mayro P. Tanyag, Curtis Jones, Camila Bacellar, Maximilian Bucher, Ken R. Ferguson, Daniela Rupp, Michael P. Ziemkiewicz, Luis F. Gomez, Adam S. Chatterley, Tais Gorkhover, Maria Müller, John Bozek, Sebastian Carron, Justin Kwok, Samuel L. Butler, Thomas Möller, Christoph Bostedt, Oliver Gessner, and Andrey F. Vilesov Helium nanodroplets are considered ideal model systems to explore quantum hydrodynamics in self-contained, isolated superfluids. Rotation of a superfluid droplet is manifested as a collection of quantum vortices. Here, the authors use single-shot femtosecond X-ray coherent diffractive imaging to investigate the shapes and vorticity of rotating superfluid 4 He droplets. They find that most of the diffraction contours exhibit noticeable ellipticity. A smaller but still significant number of distorted diffraction contours are marked by regions of high intensity concentrated along the direction of the long axis in the diffraction image, indicating the presence of extremely deformed 4 He droplets. Forward modeling of the diffraction images shows that the shapes of superfluid 4 He droplets are very similar to their classical counterparts. In particular, the existence of both axially symmetric (oblate) and, for higher angular momenta, two-lobed (triaxial prolate) droplets is revealed. The latter shapes are strongly deformed compared to the spheroidal bodies that are expected for smaller rotational speeds. The observed shapes provide direct access to the droplet angular momenta, angular velocities, and estimated number of quantum vortices inside the droplets. [Phys. Rev. B 95, 064510] Published Thu Feb 16, 2017
Keywords:
Superfluidity and superconductivity
Print ISSN:
1098-0121
Electronic ISSN:
1095-3795
Topics:
Physics
