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  • Open Access

Suppression of capillary instability in a confined quantum liquid filament

Francesco Ancilotto1,2,*, Michele Modugno3,4,5, and Chiara Fort6,7,8,†

  • *Contact author: francesco.ancilotto@unipd.it
  • †Contact author: chiara.fort@unifi.it
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Phys. Rev. A 112, 043316 – Published 15 October, 2025

DOI: https://doi.org/10.1103/f1j6-st85

Abstract

Quantum Bose-Bose mixtures with large interspecies attraction can form self-bound, liquid-like droplets stabilized by quantum fluctuations. Despite equilibrium densities much lower than those of classical liquids, these droplets exhibit finite surface tension and liquid-like behaviors. Recent experiments have demonstrated Rayleigh-Plateau instability (a paradigmatic example of capillary instability) in elongated droplets confined in an optical waveguide. Here, we consider the case of an infinite filament and extend the theoretical description to include transverse harmonic confinement. By solving the Bogoliubov–de Gennes equations within a single-component framework, benchmarked against full Gross-Pitaevskii simulations, we show that increasing confinement progressively suppresses the instability, leading to complete stabilization beyond a critical trap frequency.

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Phys. Rev. A 112, 043316– Published 15 October, 2025
  • Received 15 July 2025
  • Accepted 25 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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