- #1

- 84

- 8

Hello! I just found out about the Schiff moment. This is the paper where I encountered it, equations 3 and 4. The paper covers other things, too, that are not related to my question.

The main question I have is that, it seems like the derivation from equation 1 to 4 is purely classical (one can ignore the shielding term if necessary). They look at the next term after the electric quadrupole, which is equation 3.

As far as I remember from my electromagnetism (EM) class, the next term would be the octupole. However, they seem to get, beside the octupole (eq 6), another term, the Schiff moment (SM) (eq 5). I am pretty sure I didn't hear about the SM in my EM class, so I was wondering what is happening here? How was it hidden in the derivations in the EM classes (honestly I haven't heard of SM in general, even when googling stuff online for the class, not only in my book).

Also I thought that the normal expansion in dipole, quadrupole, octupole etc. is complete i.e. no other terms are needed. Can someone help me understand a bit this SM term, and why is it missing in classical books derivations (assuming I didn't just missed in during that class)? Thank you!

The main question I have is that, it seems like the derivation from equation 1 to 4 is purely classical (one can ignore the shielding term if necessary). They look at the next term after the electric quadrupole, which is equation 3.

As far as I remember from my electromagnetism (EM) class, the next term would be the octupole. However, they seem to get, beside the octupole (eq 6), another term, the Schiff moment (SM) (eq 5). I am pretty sure I didn't hear about the SM in my EM class, so I was wondering what is happening here? How was it hidden in the derivations in the EM classes (honestly I haven't heard of SM in general, even when googling stuff online for the class, not only in my book).

Also I thought that the normal expansion in dipole, quadrupole, octupole etc. is complete i.e. no other terms are needed. Can someone help me understand a bit this SM term, and why is it missing in classical books derivations (assuming I didn't just missed in during that class)? Thank you!

Last edited by a moderator: