Probing Quantum Turbulence in He4 by Quantum Evaporation Measurements

Ivan Amelio, Davide Emilio Galli, and Luciano Reatto
Phys. Rev. Lett. 121, 015302 – Published 5 July 2018
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Abstract

Theory of superfluid He4 shows that, due to strong correlations and backflow effects, the density profile of a vortex line has the character of a density modulation and it is not a simple rarefaction region as found in clouds of cold bosonic atoms. We find that the basic features of this density modulation are represented by a wave packet of cylindrical symmetry in which rotons with a positive group velocity have a dominant role: The vortex density modulation can be viewed as a cloud of virtual excitations, mainly rotons, sustained by the phase of the vortex wave function. This suggests that in a vortex reconnection some of these rotons become real so that a vortex tangle is predicted to be a source of nonthermal rotons. The presence of such vorticity induced rotons can be verified by measurements at low temperature of quantum evaporation of He4 atoms. We estimate the rate of evaporation and this turns out to be detectable by current instrumentation. Additional information on the microscopic processes in the decay of quantum turbulence will be obtained if quantum evaporation by high energy phonons should be detected.

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  • Received 7 February 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.015302

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Ivan Amelio1,2, Davide Emilio Galli1, and Luciano Reatto1,*

  • 1Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, via Celoria 16, I-20133 Milano, Italy
  • 2Dipartimento di Fisica, Università di Trento, via Sommarive 14, I-38050 Povo, Italy

  • *luciano.reatto@mi.infn.it

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Issue

Vol. 121, Iss. 1 — 6 July 2018

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