The Vortex Phase Diagram for Rotating Superfluid 3He-B
Robert C. Regan, Joshua J. Wiman and J. A. Sauls
- Address: Department of Physics, Northwestern University, Evanston, IL 60208
- Date: August 15, 2019
Physical Review B 101, 024517 (2020)
We present the first theoretical calculation of the pressure-temperature-field phase diagram for the vortex phases of rotating superfluid 3He-B. Based on a strong-coupling extension of the Ginzburg-Landau theory that accounts for the relative stability of the bulk A and B phases of 3He at all pressures, we report calculations for the internal structure and free energies of distinct broken-symmetry vortices in rotating superfluid 3He-B. Theoretical results for the equilibrium vortex phase diagram in zero field and an external field of H=284 G parallel to the rotation axis, H||Ω, are reported, as well as the supercooling transition line, T*V(p,H). In zero field the vortex phases of 3He-B are separated by a first-order phase transition line TV(p) that terminates on the bulk critical line Tc(p) at a triple point. The low-pressure, low-temperature phase is characterized by an array of singly-quantized vortices that spontaneously breaks axial rotation symmetry, exhibits anisotropic vortex currents and an axial current anomaly (D-core phase). The high-pressure, high-temperature phase is characterized by vortices with both bulk A phase and β phase in their cores (A-core phase). We show that this phase is metastable and supercools down to a minimum temperature, T*V(p,H), below which it is globally unstable to an array of D-core vortices. For H >~60 G external magnetic fields aligned along the axis of rotation increase the region of stability of the A-core phase of rotating 3He-B, opening a window of stability down to low pressures. These results are compared with the experimentally reported phase transitions in rotating 3He-B.
- Comment: 14 pages, 11 figures