Supercooling of the A phase of 3He

• Published in: Nature communications 2023-01, Vol.14 (1), p.148-148, Article 148
• Main Authors: Tian, Y., Lotnyk, D., Eyal, A., Zhang, K., Zhelev, N., Abhilash, T. S., Chavez, A., Smith, E. N., Hindmarsh, M., Saunders, J., Mueller, E., Parpia, J. M.
• Format: Article
• Language: English
• Subjects: 639/766/119/2792; 639/766/119/999; 639/766/530/2795; Fluids; Humanities and Social Sciences; Magnetic fields; Mathematical models; multidisciplinary; Nucleation; Order parameters; Phase transitions; Science; Science (multidisciplinary); Supercooling; Superfluidity; Transition temperature; Transition temperatures; Universe
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-35532-7

Because of the extreme purity, lack of disorder, and complex order parameter, the first-order superfluid 3 He 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 3 He can be exploited to model transitions in the early universe. The A–B transition in superfluid 3 He is a pure experimental model system to study first-order phase transitions in the early Universe. Tian et al. observe the path dependence of the supercooling of the A phase in a wide parameter range and provide explanations for the heterogeneous nucleation of the B phase.