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Lookup NU author(s): Dr Luca Galantucci, Professor Carlo Barenghi
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Recent work has highlighted the remarkable properties of quantum turbulence in superfluidhelium II, consisting of a disordered tangle of quantised vortex lines which interact with each otherand reconnect when they collide. According to Landau’s two-fluid theory, these vortex lines move ina surrounding of thermal excitations called the normal fluid. Until now, the normal fluid has oftenbeen considered a passive background which simply provides the vortex lines with a mechanism fordissipating their kinetic energy into heat. Using a model which fully takes into account the two-wayinteraction between the vortex lines and the normal fluid, here we show numerically that each vortexline creates a macroscopic wake in the normal fluid that can be larger than the average distancebetween vortex lines; this is surprising, given the microscopic size of the superfluid vortex coreswhich induce these wakes. We show that in heat transfer experiments, the flow of the normal fluidcan therefore be described as the superposition of an imposed uniform flow and wakes generated bythe vortex lines, leading to non-classical statistics of the normal fluid velocity. We also argue thatthis first evidence of independent fluid structures in the thermal excitations postulated by Landaumay be at the root of recent, unaccounted for, experimental findings.
Author(s): Galantucci L, Krstulovic G, Barenghi CF
Publication type: Article
Publication status: Published
Journal: Physical Review Letters
Year: 2025
Volume: 136
Issue: 1
Print publication date: 09/01/2026
Online publication date: 02/01/2026
Acceptance date: 22/10/2025
Date deposited: 02/11/2025
ISSN (print): 0031-9007
ISSN (electronic): 1079-7114
Publisher: American Physical Society
URL: https://doi.org/10.1103/xnyc-321m
DOI: 10.1103/xnyc-321m
Data Access Statement: The data that support the findings of this article are openly available. L. Galantucci, G. Krstulovic, C. F. Barenghi (2025), 10.5281/zenodo.17457098. https://doi.org/10.5281/zenodo.17457098
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