Schäfer, A; Müller, B; Greiner, W, *Dirakovskiye chastitsy v polye magnitnykh monopolyei i silyanykh Elyektrichyeskikh zaryadov*,
Il Nuovo Cimento A Series 10, vol. 89 no. 4
(1985),
pp. 437-451 [doi] .
**Abstract:**

*The field of a magnetic pointlike monopole acts in a similar way on a charged Dirac particle as the field of a very strong electric point charge. To explore this parallel we construct a field solution for an extended magnetic-charge distribution. In contrast to what is found for extended electric charges, the Hamiltonian remains non-self-adjoint for an extended magnetic monopole. This suggests that there exists a fundamental difference between the two cases. In particular, the appearance of undefined states for point monopoles is not a consequence of the mere strength of the magnetic-monopole charge, which has a minimum value fixed by Dirac's quantization condition. © 1985 Società Italiana di Fisica.*