I have always got thrilled after reading about Polarization and Magnetization. The former was the first thing I read where QM would have been applied (though I never got a chance to know how). Now, I was learning Magnetization and Magnetic materials. And as I see, it all ends up at the circulating currents - Amperian currents, which "basically" would just be the spin. Spin is an interesting thing to note. As far as I know, Stern-Gerlach experiment was the first evidence of spin. The light split into a finite number of beams. Why? Maybe because that's how the nature is. There is a quantization of angular momentum. It can only take a finite number of values. Nobody knows the basic details.
Now, my question here is how would polarization look like in QM(you may use mathematics of QM, though I know only the basics)? How would it explain it better than CM does?
And how would magnetization look in QM? Dia-, para-, ferro- and all those. Diamagnetism might just be the basic only and can be understood using CM but there is one mean square radius which comes in(or I should say we manipulate it such a way classically so that it becomes same as in QM) the formula of induced diamagnetic moment(for an atom) which seems quite strange in CM(you know the radius of course). Paramagnetism, Ferromagnetism and others are purely quantum mechanical. So, yeah please try to explain them.
It would be nice if an explanation of the "Lande's g factor" is explained before the Magnetization explanation.
Thanks in anticipation!