The A-B transition in superfluid helium-3 under confinement in a thin slab geometry

Nikolay Zhelev, T.S. Abhilash, E.N. Smith, Robert Bennett, Xavier Rojas, Lev Levitin, John Saunders, Jeevak Parpia

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The influence of confinement on the phases of superfluid helium-3 is studied using the torsional pendulum method. We focus on the transition between the A and B phases, where the A phase is stabilized by confinement and a spatially modulated stripe phase is predicted at the A–B phase boundary. Here we discuss results from superfluid helium-3 contained in a single 1.08-μm-thick nanofluidic cavity incorporated into a high-precision torsion pendulum, and map the phase diagram between 0.1 and 5.6 bar. We observe only small supercooling of the A phase, in comparison to bulk or when confined in aerogel, with evidence for a non-monotonic pressure dependence. This suggests that an intrinsic B-phase nucleation mechanism operates under confinement. Both the phase diagram and the relative superfluid fraction of the A and B phases, show that strong coupling is present at all pressures, with implications for the stability of the stripe phase.
Original languageEnglish
Article number15963
Pages (from-to)1-9
Number of pages9
JournalNature Communications
Publication statusPublished - 3 Jul 2017


  • topological superfluid
  • superfluid 3He
  • 1st order phase transition
  • phase transitions
  • early universe

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