Electron Bubbles in Superfluid 3 He-A: Exploring the Quasiparticle–Ion Interaction

Oleksii Shevtsov, J. A. Sauls*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


When an electron is forced into liquid 3He, it forms an “electron bubble”, a heavy ion with radius, R≃ 1.5 nm, and mass, M≃100m3, where m3 is the mass of a 3He atom. These negative ions have proven to be powerful local probes of the physical properties of the host quantum fluid, especially the excitation spectra of the superfluid phases. We recently developed a theory for Bogoliubov quasiparticles scattering off electron bubbles embedded in a chiral superfluid that provides a detailed understanding of the spectrum of Weyl Fermions bound to the negative ion, as well as a theory for the forces on moving electron bubbles in superfluid 3He-A (Shevtsov and Sauls in Phys Rev B 94:064511, 2016). This theory is shown to provide quantitative agreement with measurements reported by the RIKEN group (Ikegami et al. in Science 341(6141):59, 2013) for the drag force and anomalous Hall effect of moving electron bubbles in superfluid 3He-A. In this report, we discuss the sensitivity of the forces on the moving ion to the effective interaction between normal-state quasiparticles and the ion. We consider models for the quasiparticle–ion (QP–ion) interaction, including the hard-sphere potential, constrained random-phase-shifts, and interactions with short-range repulsion and intermediate-range attraction. Our results show that the transverse force responsible for the anomalous Hall effect is particularly sensitive to the structure of the QP–ion potential and that strong short-range repulsion, captured by the hard-sphere potential, provides an accurate model for computing the forces acting on the moving electron bubble in superfluid 3He-A.

Original languageEnglish (US)
Pages (from-to)340-353
Number of pages14
JournalJournal of Low Temperature Physics
Issue number5-6
StatePublished - Jun 1 2017


  • Broken parity and time-reversal
  • Chirality
  • Electron bubbles
  • Scattering theory
  • Superfluid He
  • Weyl Fermions
  • t Matrix

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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