Since the boundary between the two superfluids must remain aligned along the radial direction, the superfluid present at this boundary must rotate like a classical object. (sciencedaily.com)
«The shortest boundary [between the components] is in the radial direction,» Dr. Angela White, first author on the study, explains. (sciencedaily.com)
As predicted, the polarization has a radial direction in most parts of the disk, but at the edge of the disk, the direction is flipped perpendicular to the radial direction. (sciencedaily.com)