Persistent currents in spinor condensates
  We create and study persistent currents in a toroidal two-component Bose gas, consisting of $^{87}$Rb 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 polarisation 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-polarisation vector, rather than its orientation in spin space, is relevant for supercurrent stability. 
Scott Beattie, Stuart Moulder, Richard J. Fletcher, Zoran Hadzibabic
cond-mat.quant-gas cond-mat.stat-mech cond-mat.supr-con physics.atom-ph quant-ph