Supercurrent induced by multipoles in nonmagnetic spin-2 Bose-Einstein condensates*

In spinor Bose-Einstein condensates (BECs), a supercurrent is known to be induced by the magnetic degrees of freedom when the magnitude of the spin vector is finite. On the other hand, when a spinor BEC is nonmagnetic, the supercurrent originatingfrom the magnetic degrees of freedom is absentfor a spin-1 BEC; however, it has remained to beclarified if it is essentially zero for any spin degrees of freedom. We show that a supercurrent can be induced by magnetic multipoles for a non-magnetic spin-2 BEC. We analytically derive asuperfluid in a nonmagnetic spin-2 BEC that involves components originatingfrom the magnetic degrees of freedom. We also numerically demonstrate that these components can be induced by aspatially dependent magnetic field via the quadratic Zeeman effect.