@AF Hello,

I would like to make sure that the interpretation of the phenomenon of superfluidity is correctly understood in terms of the Gross-Pitaevskii (GP) equation. The HP equation has symmetry with respect to spatial rotations and displacements, and hence the momentum and angular momentum for it are the integrals of motion. Nothing prevents me from setting in the initial conditions for this equation a field of any form, including those with energetically unfavorable perturbations (corresponding to a slow external action).However, in view of the presence of ukase integrals of motion, if these perturbations are characterized by an angular momentum, then it will persist.Its "energy disadvantage", it seems to me, is manifested in the fact that due to the nonlinear mechanisms incorporated in the GP, low-frequency spatial modes are converted to high-frequency spatial angular modes, which is interpreted as a temperature increase, and not as an increment of the angular momentum after the interaction of the superfluid matter with walls of the rotating vessel.