Since magnetic moment come from the circulation of charge, what is the origination of the electron's magnetic moment? Because spin of electron is not the classical spin of particle. Can we say that corresponding to every angular momentum there is a magnetic moment and since spin angular momentum is conformed from Stern-Gerlach experiment so there is a magnetic moment.
[Physics] Magnetic moment of electron
angular momentummagnetic-momentquantum mechanicsquantum-spin
Best Answer
It's not true that a magnetic moment always comes from the circulation of charge. An electron's magnetic moment cannot originate entirely from circulation of charge in some internal structure of the electron, because then its g-factor (essentially the ratio of magnetic moment to spin) would then have to equal 1, when in fact it's approximately 2. Similarly, an electron's angular momentum can't come entirely from this type of internal motion, since it would then have to be a whole-number multiple of $\hbar$.
As far as we know, the electron is a pointlike particle without any internal structure such as preons.
I don't think so, since photons have spin, but they have no magnetic moment. In general, QED is the theory that predicts $g$ factors, and the $g$ factors are deduced from the more fundamental principles of QED, not just postulated.