I'm studying atomic physics this semester and just like my previously two semesters of quantum mechanics. i always end up in your videos for help. You really always say the things Griffiths leaves out that makes me get it. Thank you!
I always assumed that magnetic moments were the only way to measure spin. But that sounds wrong now if there's a fudge factor for it. So how is spin itself measured?
Is not gamma negative? I mean gamma=(-e)/m the why do we neglect the negative sign. At the end the direction of precession around the applied field alters if we consider the - sign!
One quick stupid clarification: At 31:15 you say the particle will be deflected up or down based on the spin. More accurately, the majority of the deflection will be determined by the particle's charge and not its magnetic moment right? There will be a delta contribution based on the magnetic moment but on the whole the actual direction is based on charge.
It is not based on charge. When the atoms of say, silver, are exposed to the magnetic field, the magnetic moment produced by the extra electron will be deflected by the mechanical force that the magnetic field exerts. If the spin of the electron is down, and the magnetic field B is going down, if you zoom in on it, the electron will actually be attracted to the north part of the magnetic field, which will bring the atom the electron is in... upwards to some angle. The north part of that magnet is attracting the down-spinning magnetic moment of the electron, and that extra valence electron turns out to carry the whole damn atom upwards with it. Likewise, when the valence electron is spinning up, it will be attracted to the south part of the magnetic field in that stern-gerlach experiment, and the beam containing all of the atoms will head downwards. Sometimes you have to feel magnets yourself just to feel that mechanical energy or magnetic energy the magnets have, versus the electrical (charge) energy. I hope this makes sense and I tried to answer this the best I could.
Thank you, I always wanted to see the Larmor frequency being derived from the hamiltonian and expected values. I had an intuitive idea but it just didn't seem right to not know from where it came from in NMR classes
