Universal Formula for the Expectation Value of the Radial Operator under   the Aharonov-Bohm Flux and the Coulomb Field
  A useful and universal formula for the expectation value of the radial operator in the presence of the Aharonov-Bohm flux and the Coulomb Field is established. We find that the expectation value $< r^{\lambda}>$ $(-\infty \leq \lambda \leq \infty)$ is greatly affected due to the non-local effect of the magnetic flux although the Aharonov-Bohm flux does not have any dynamical significance in classical mechanics. In particular, the quantum fluctuation increases in the presence of the magnetic flux due to the Aharonov-Bohm effect. In addition, the Virial theory in quantum mechanics is also constructed for the spherically symmetric system under the Aharonov-Bohm effect. 
W.F. Kao, Y.M. Kao, and D.H. Lin