Quantum Mechanics 8a - Spin I

We explore how the "spinning" of the electron explains why the number 2 arises in several atomic experiments.

Comments, suggestions and constructive criticism are always welcome. Ratings are appreciated also.

[AntiCSFC]

Uploaded 10 years ago? I find this now? Thats crazy. The way you are showing ACTUAL experiment results leading to every new fact about reality is great and unparalleled.

[lalleyfamily]

I have watched the first 15 videos, some more than once. I promise I will do so again, after I finish them all. Thank you for all the effort you put into these videos. I love how you explain the wave equations.

[Richardj]

Thanks again, I download these and watch them a couple of times so the sink in. Thanks for all the hard work.

[avdheshkumarsharma]

Thanks for making these...loved ur way of telling in short and unique way..❤️

[SquidKing]

literally saving my life right now, decided to try and derive Dirac's equation even though I've never covered spin, angular momentum, Schrodinger's equation or the uncertainty principle or anything. These videos are really getting me through 💯

[viascience]

Spin is one of those "nobody understands it" things. The math works out, but it means exactly is a bit mysterious.

[LookingGlassUniverse]

I've just discovered your videos, great job!!

[joshuacrosby]

I love your videos. I am a budding young* theoretical physics enthusiasts... and am learning much... thank you very much.

[Chopstewie]

So there is 'something' that acts kind of like momentum that is generated by 'something' that we call "spin" which is not the product of anything "actually" spinning. Got it, for a second there I was confused :)

[rossholst]

What mass are we using when we try to calculate the velocity rotational velocity of an electron? Are we using the rest mass of the electron?

Is the mass of the electron not dependent on the velocity with which it is traveling? So when at relativistic speeds would the inertial mass of the electron not be significantly larger than the rest mass of the electron?

[piotrprs]

Preatty accurate explanation about QM -> spin

[viascience]

"snazziness" is as good a term as I've ever heard for whatever the hell it is that's going on in there! ;-)

[totoritko]

Can't wait for the next part! Thanks for the vid!

[synchronyJEM]

This is just speculation and I'm not that qualified enough at all to dwell in these matters, but I'll try to dig up what is done on the matter.

Also, in your last video (Spin II), I find it curious that the Higgs Boson is the only elementary particle to have no spin (or having a "0" spin qualifies as having a spin?) - I'll post this question on that video also

[viascience]

Yes, Michelson was know for being a fanatic about accuracy. An experimentalist of the highest order.

[岡安一壽]

What is Spin ? I think the answer is phase shift (= shift in coordinate).
1. I think the de Broglie waves of multiple particles in one quantum state are connected in series, and the each wave shift msλ at the connecting point. (ms:spin quantum number, λ:wave length)Let us consider a case in which two electrons are in one quantum state [n, l, ml, ms=+1/2].
The de Broglie wave of 1st electron shifts +λ/2 in coordinate. And the de Broglie wave of 2nd electron shifts +λ/2+λ/2 in coordinate. Accordingly the two waves destructively interfere.
[the Pauli exclusion principle]
2. Suppose that two electrons are moving in a single orbit, and suppose that the de Broglie wave of one electron shifts +λ/2 in coordinate and the de Broglie wave of another electron shifts -λ/2 in coordinate.
The two waves have the shift of exactly one wavelength, which leads to a constructive interference of the wave, making it possible for the two particles to move in the same orbit.
[the 4th quantum number]
3. The variable of wave function Φ{φez･(r ×p)} in φ direction has angular momentum r ×p.
Accordingly, the shift in coordinate msλ change the angular momentum as follows: ml(h/2π)→ ml(h/2π)+ms(h/2π).

I'm sorry that I'm not good at English.

[stevewhitt]

You should explain electron spin as a 2D Complex Vector.

[jessstuart]

4:30 Had to think about this for a minute. Silver and Hydrogen have an outer electron that is in an s orbital (5s for silver, 1s for hydrogen). Because the s orbital has no angular momentum, any magnetic dipole moment seen in the experiment has to come from the electron itself.

[Chopstewie]

So to hazard sounding dense: Electron appear to/have a magnetic dipole, which -could- be explained by rotation of the particle, but since such rotation can't be accounted for by a classical understanding the electron instead has some kind of "snazziness" that intrinsically grants it the aforementioned dipole. And this snazziness only appears to have a magnitude of 1/2 or -1/2 for any electron?

[bburns]

That's interesting that higher quantum numbers -> classical mechanics, and that the electron orbitals become more like classical orbits - somehow I missed that at school. We solved the first orbital for Hydrogen numerically, but it would have been interesting to plug in larger numbers also and see them becoming more circular. Anyway, thanks for the video - on to part b...