Progress of studies on rotating ultracold atoms

The macroscopic quantization of circulating current is an attractive property of superfluids. The realization of Bose-Einstein condensation (BEC) offers us a new testing ground, in which we can explore superfluids thoroughly. Vortex line excitation and even vortex lattices have been experimentally observed. When the angular velocity is further increased, the vortex lattice in BEC will melt into a new strongly correlated system, a quantum Hall liquid. We review the progress of both theoretical and experiment research on rotating cold atoms.