2006/07/05 by Biao Wu, Wu, Biao, Junren Shi +1
Physics and Astronomy · #FOS: Physical sciences #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0607098
extensive revision, 4 pages and 4 figures
arxiv created 2007/01/16 · arxiv updated 2009/12/01
In contrast to the homogeneous superfluid which has only one critical velocity, there exist two critical velocities for a superfluid in a periodic potential. The first one, which we call inside critical velocity, is for a macroscopic impurity to move frictionlessly in the periodic superfluid system; the second, which is called trawler critical velocity, is the largest velocity of the lattice relative to the lab frame for the superfluidity to maintain. The results are relevant to the superfluidity observed in the Bose-Einstein condensate in an optical lattice and supersolid helium.