Path integral solution for an electron moving in the field of a Dirac monopole

In this paper the path integral for an electron moving in the field of a Dirac monopole is calculated. The energy spectrum and the wave-functions are explicitly evaluated. In addition the effect of a spherically shaped δ-function perturbation on the original continuous spectrum is investigated. It is found that a finite number of energy levels depending on the angular momentum number J can exist which are determined by a transcendental equation involving the partial wave Green function of the unperturbed Dirac monopole problem