Effect of a rotating potential on a quantum particle

The dynamical problem of particle rotation in the classical and quantum cases is considered. The effect of a rotating potential on a quantum particle in a ring is analyzed. We find that in the quantum case the particle will be fully rotated only at discrete values of frequency. For large energies a particle generally does not rotate at all, aside from a neighborhood around the frequencies of full rotation whose width depends on the energy of the initial wave packet and the potential strength. The analogies with the classical case are discussed. We also discuss the relationship to flux problems and thermodynamic equilibrium.