Supercooling of the A phase of 3He

Y Tian; D Lotnyk; A Eyal; K Zhang; N Zhelev; T S Abhilash; A Chavez; E N Smith; M Hindmarsh; J Saunders; E Mueller; J M Parpia

doi:10.1038/s41467-022-35532-7

Supercooling of the A phase of ³He

Nat Commun. 2023 Jan 10;14(1):148. doi: 10.1038/s41467-022-35532-7.

Authors

Y Tian¹, D Lotnyk¹, A Eyal^{1

2}, K Zhang^{3

4}, N Zhelev^{1

5}, T S Abhilash^{1

6}, A Chavez¹, E N Smith¹, M Hindmarsh^{3

4}, J Saunders⁷, E Mueller¹, J M Parpia⁸

Affiliations

¹ Department of Physics, Cornell University, Ithaca, NY, 14853, USA.
² Physics Department, Technion, Haifa, Israel.
³ Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, BN1 9QH, UK.
⁴ Department of Physics and Helsinki Institute of Physics, University of Helsinki, PL 64, FI-00014, Helsinki, Finland.
⁵ Center for Applied Physics and Superconducting Technologies, Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA.
⁶ VTT Technical Research Centre of Finland Ltd, Espoo, Finland.
⁷ Department of Physics, Royal Holloway University of London, Egham, TW20 0EX, Surrey, UK.
⁸ Department of Physics, Cornell University, Ithaca, NY, 14853, USA. jmp9@cornell.edu.

Abstract

Because of the extreme purity, lack of disorder, and complex order parameter, the first-order superfluid ³He A-B transition is the leading model system for first order transitions in the early universe. Here we report on the path dependence of the supercooling of the A phase over a wide range of pressures below 29.3 bar at nearly zero magnetic field. The A phase can be cooled significantly below the thermodynamic A-B transition temperature. While the extent of supercooling is highly reproducible, it depends strongly upon the cooling trajectory: The metastability of the A phase is enhanced by transiting through regions where the A phase is more stable. We provide evidence that some of the additional supercooling is due to the elimination of B phase nucleation precursors formed upon passage through the superfluid transition. A greater understanding of the physics is essential before ³He can be exploited to model transitions in the early universe.

Abstract

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