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Would a rotating sphere of magnetic monopole charge have electric moment ?

In a duality transformation $E\rightarrow B\cdot c$ etc. how is the magnetic moment translated $m = I\cdot S $ ? $M_{el} = \frac{d}{dt}(-\frac{Q_{mag}}{c})\cdot S$ ?

A more general question would a sphere charged with monopoles have other moments that the monopole in the multipole expansion ? Like electron is predicted to have electric dipole moment also.

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  • $\begingroup$ Wouldn't a monopole, by definition, have no higher moments? $\endgroup$ – John Rennie Sep 25 '12 at 16:28
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    $\begingroup$ No, John, the OP talks about a rotating sphere with magnetic monopole charge - and it will indeed have dipole moment. It's the electromagnetic dual of the claim that the rotating charged sphere contains currents and they create magnetic field - of a magnetic dipole. Imagine the currents along the parallels of latitude. Just exchange E and B and you get what the OP is doing. $\endgroup$ – Luboš Motl Sep 25 '12 at 16:44
  • $\begingroup$ Thanks. Does rotating magnetic charge have magnetic dipole moment also ? The electron has electric dipole moment for some reason. $\endgroup$ – user12445 Sep 25 '12 at 16:58
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    $\begingroup$ No, the electron dipole moment is very small, $10^{-38}$ e.cm, and it's only nonzero because of CP-violation. If there are new sources of CP-violation, it may be slightly larger - but just notice that the displacement distance is just $10^{-38}$ centimeters, shorter than the Planck length, tiny. Without fancy things like CP-violation, the electron has no electric dipole moment, and the same thing would hold for a macroscopic rotating magnetic monopole. $\endgroup$ – Luboš Motl Sep 25 '12 at 17:25

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