Persistent Currents in Spinor Condensates

We create and study persistent currents in a toroidal two-component Bose gas, consisting of~Rb-87 atoms in two different spin states. For a large spin-population imbalance we observe supercurrents persisting for over two minutes. However, we find that the supercurrent is unstable for spin polarization below a well-defined critical value. We also investigate the role of phase coherence between the two spin components and show that only the magnitude of the spin-polarization vector, rather than its orientation in spin space, is relevant for supercurrent stability [Phys. Rev. Lett. 110, 025301 (2013)].