Fractional quantum hall effect: Superfluidity, magneto-rotons and fractionally charged vortices

The fractional quantum Hall effect is a remarkable macroscopic quantum phenomenon in which the Hall resistivity of a two-dimensional electron gas is accurately quantized in units of h/e². This nearly dissipationless state is analogous to superfluidity with the collective excitations being phonons, magneto-rotons and fractionally charged vortices.