Dependence of the superfluidity criterion on the capillary radius

摘要

We replace the conditions oil the capillary boundary with the Born-Karman periodic conditions, i.e., we consider a two-dimensional torus of radius L-2. If the velocity of a superfluid liquid exceeds 8 pi h/(mL(2)), then it brakes because of the friction against the eddy formed by pairs (similar to the pairs in the Andreev reflection).