Connecting shear flow and vortex array instabilities in annular atomic superfluids
Year: 2024
Authors: Hernandez-Rajkov D., Grani N., Scazza F., Del Pace G., Kwon WJ., Inguscio M., Xhani K., Fort C., Modugno M., Marino F., Roati G.
Autors Affiliation: Univ Florence, European Lab Nonlinear Spect, Sesto Fiorentino, Italy; CNR, European Lab Nonlinear Spect, Ist Nazl Ott, Sesto Fiorentino, Italy; Univ Florence, Dept Phys & Astron, Sesto Fiorentino, Italy; Univ Trieste, Dept Phys, Trieste, Italy; Ulsan Natl Inst Sci & Technol, Dept Phys, Ulsan, South Korea; Campus Biomed Univ Rome, Dept Engn, Rome, Italy; Univ Basque Country, Dept Phys, UPV EHU, Bilbao, Spain; Basque Fdn Sci, Ikerbasque, Bilbao, Spain; Univ Basque Country, EHU Quantum Ctr, UPV EHU, Leioa, Spain; Ist Nazl Fis Nucl, Sez Firenze, Sesto Fiorentino, Italy.
Abstract: At the interface between two fluid layers in relative motion, infinitesimal fluctuations can be exponentially amplified, inducing vorticity and the breakdown of laminar flow. While shear flow instabilities in classical fluids have been extensively observed in various contexts, controlled experiments in the presence of quantized circulation are quite rare. Here we observe how the contact interface between two counter-rotating atomic superflows develops into an ordered circular array of quantized vortices, which loses stability and rolls up into vortex clusters. We extract the instability growth rates and find that they obey the same scaling relations across different superfluid regimes, ranging from weakly interacting bosonic to strongly correlated fermionic pair condensates. Our results establish connections between vortex arrays and shear flow instabilities, suggesting a possible interpretation of the observed quantized vortex dynamics as a manifestation of the underlying unstable flow. Moreover, they open the way for exploring out-of-equilibrium phenomena such as vortex matter phase transitions and the spontaneous emergence and decay of two-dimensional quantum turbulence. Two adjacent layers flowing at different velocities in the same fluid are subject to flow instabilities. This phenomenon is now studied in atomic superfluids, revealing that quantized vortices act as both sources and probes of the unstable flow.
Journal/Review: NATURE PHYSICS
Volume: 20 (6) Pages from: 939 to: 944
More Information: We thank I. Carusotto, N. Cooper and G. Modugno for their valuable comments on the manuscript and the Quantum Gases group at LENS for fruitful discussions. This work was supported by the European Research Council (ERC) under grant agreement no. 307032, the Italian Ministry of University and Research under the PRIN2017 project CEnTraL and PNRR project PE0000023-NQSTI, the European Union’s Horizon 2020 research and innovation programme under the Qombs project FET Flagship on Quantum Technologies grant agreement no. 820419. W.J.K. acknowledges support from the Research Fund (1.220137.01) of UNIST (Ulsan National Institute of Science and Technology). M.M. acknowledges support from grant no. PID2021-126273NB-I00 funded by MCIN/AEI/10.13039/501100011033 and ’ERDF – A way of making Europe’, and from the Basque Government through grant no. IT1470-22. F.S. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 949438) and from the Italian MUR under the FARE programme (project FastOrbit).KeyWords: Kelvin-helmholtz Instability; Turbulence; Stability; Dynamics; VorticesDOI: 10.1038/s41567-024-02466-4Citations: 2data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-09-15References taken from IsiWeb of Knowledge: (subscribers only)