Off-Diagonal Long-Range Order in Bose Liquids: Irrotational Flow and Quantization of Circulation

Off-Diagonal Long-Range Order in Bose Liquids: Irrotational Flow and Quantization of Circulation

        Gang Su1,2,* and Masuo Suzuki2,†

1Department of Physics, Graduate School at Beijing, University of Science and Technology of China, Chinese Academy of Sciences, P.O. Box 3908, Beijing 100039, China

2Department of Applied Physics, Faculty of Science, Science University of Tokyo, 1-3, Kagurazaki, Shinjuku-ku, Tokyo 162, Japan

Phys. Rev. Lett. 86, 2708 – Published 26 March 2001  Received 18 September 2000

ABSTRACT

On the basis of gauge invariance, it is proven in an elementary and straightforward manner, but without invoking any ad hoc assumption, that the existence of off-diagonal long-range order in one-particle reduced density matrix in Bose liquids implies both the irrotational flow in a simply connected region and the quantization of circulation in a multiply connected region, the two fundamental properties of a Bose superfluid. The origin for both is the phase coherence of condensate wave functions. Some relevant issues are also addressed.

DOI:https://doi.org/10.1103/PhysRevLett.86.2708