Mutual friction and vortex Hall angle in a strongly interacting Fermi superfluid
We investigate the two-dimensional motion of a single vortex orbiting a pinned anti-vortex in a unitary Fermi superfluid. By analyzing its trajectory, we measure the yet-unknown longitudinal and transverse mutual friction coefficients, which quantify the vortex-mediated coupling between the normal and superfluid components. Both coefficients increase while approaching the superfluid transition. They provide access to the vortex Hall angle, which is linked to the relaxation time of the localized quasiparticles occupying Andreev bound states within the vortex core, and to the vortex Reynolds number Re<sub>α</sub> associated with the transition from laminar to quantum turbulent flows. We compare our results with numerical simulations and an analytic model originally formulated for superfluid <sup>3</sup>He, finding good agreement. Our work suggests that vortex dynamics in unitary Fermi superfluids is essentially affected by the interplay between delocalized thermal excitations and vortex-bound quasiparticles. Further, it provides a novel testbed for studying vortex dynamics at finite temperatures.
Authors
- N. Grani (ORCID: https://orcid.org/0000-0001-6107-9726)
- Michele Pini (ORCID: https://orcid.org/0000-0001-5522-5109)
- Marcia Frómeta Fernández (ORCID: https://orcid.org/0000-0003-4937-8306)
- Diego Hernández-Rajkov (ORCID: https://orcid.org/0009-0002-1908-4227)
- P. Pieri (ORCID: https://orcid.org/0000-0001-8295-805X)
- G. Roati (ORCID: https://orcid.org/0000-0001-8749-5621)
- Gabriel Wlazłowski (ORCID: https://orcid.org/0000-0002-7726-5328)
- Giulia Del Pace (ORCID: https://orcid.org/0000-0002-0882-2143)
- Piotr Magierski (ORCID: https://orcid.org/0000-0001-8769-5017)
- Cyprien Daix (ORCID: https://orcid.org/0009-0000-7676-8508)
- Francesco Scazza (ORCID: https://orcid.org/0000-0001-5527-1068)
Institutions
- Warsaw University of Technology (PL)
- Centre National de la Recherche Scientifique (FR)
- University of Trieste (IT)
- University of Augsburg (DE)
- University of Washington (US)
- Université Paris Sciences et Lettres (FR)
- Laboratoire Kastler Brossel (FR)
- École Normale Supérieure - PSL (FR)
- Sorbonne Université (FR)
- Max Planck Institute for the Physics of Complex Systems (DE)
- National Institute of Optics (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (IT)
- University of Florence (IT)
- University of Bologna (IT)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-11-21
- DOI
- https://doi.org/10.1038/s41467-025-64992-w
- Citations
- 1
- Primary Topic
- Quantum, superfluid, helium dynamics
- Type
- article
- Field-Weighted Citation Impact
- 1.25
Funders
- European Commission
- China Scholarship Council
- Infrastruktura PL-Grid
- HORIZON EUROPE Framework Programme