Spin 1/2 in a B-field
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- Опубликовано: 13 май 2013
- The behavior of the spin 1/2 system in a magnetic field is interesting experimentally since particle with spin have magnetic dipole moments. This lecture discusses the effects of magnetic energy and magnetic force on such dipoles, resulting in Larmor precession and quantized deflection in the Stern-Gerlach experiment. (This lecture is part of a series for a course based on Griffiths' Introduction to Quantum Mechanics. The Full playlist is at ruclips.net/user/playlist?list=...)
a²+b²=0 was driving me insane lol
Hell yeah!🤧
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!
This is amazing, Thank you so much. I just have to inform you that videos this concise and clear on these topics are extremely rare. Keep it up.
Very solid videos, love ur content, extremely helpful. Given these were made years ago the quality is better than videos made today
Very clear! Now I get it! I Thank you and keep up the good work!
Than you very much, this helped me a lot!!
Keep up this good work bro ;D
Excellent lecture!!
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?
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
Thank you so much you save my quantum final exam
hi, at 20:57, I think there should be a minus sign for , or have I miscalculate?
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!
please explain how do we write the expressions for a and b in term of alpha??????
what is the answers of understanding's question??
would anybody know hwo to find the expectation value of speed in any arbitrary direction in the larmor precession?
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.
But these silver atoms are neutral. Aren't they ?
@@manishsingh-vk8if Its based on the spin of the outermost unpaired electron, that's what is meant with the extra electron.
Had to set the playback speed to 0.75 that was way too fast man