Remarks on the Current-Carrying State of Hall Superfluids

I discuss in an elementary and self-contained way the nature of the current-carrying state in Hall superfluids. The explicit connection of fractional charge and rationality of the filling fraction $\nu$ with quantization of angular momentum, and the discussion of the preferred velocity profile for bulk current flows may be new; the latter might provide an interesting experimental handle on a fundamental aspect of quantum superfluidity.