Mass flows and angular momentum density for px + ipy paired fermions in a harmonic trap

We present a simple two-dimensional model of a px + ipy superfluid in which the mass flow that gives rise to the intrinsic angular momentum is easily calculated by numerical diagonalization of the Bogoliubov-de Gennes operator. We find that, at zero temperature and for constant director l, the mass flow closely follows the Ishikawa–Mermin–Muzikar formula jmass=12curl/(ρℏl/2).