24. Addition of Angular Momentum

MIT 8.05 Quantum Physics II, Fall 2013
Instructor: Barton Zwiebach

In this lecture, the professor talked about Feynman-Hellman lemma, addition of angular momentum, spin-orbit coupling, etc.

License: Creative Commons BY-NC-SA

[GiI]

This guy is a fantastic lecturer. I wish I'd had someone like him both times I took quantum.

[aneedfortheory]

I only intended to watch 30 minutes of this. However, I am captivated. Incredibly precise lecturer. Only the best at MIT I presume. Hats off to you professor!

[galdali]

I struggled with my homework, then I watched this lecture and everything became easier. This guy is a great lecturer!

[xiaojunhuang]

A truly fantastic teacher in all respects

[emorell]

I'm just here wondering who could dislike such a great lecture.

[ahiaamrosi]

finally a good explanation of the Runge-Lentz vector

[岡安一壽]

I think that an electron has shift in coordinate (1/2π)msλ in r-direction. [ms: spin quantum number, λ: wave length] Accordingly, the angular momentum is as follows: (De Broglie equation: p=h/λ)
And the magnetic moment is as follows: (area)･(electric
(q/2m)pr+2(q/2m)ms(h/2π)= (q/2m)L+2(q/2m)S.
Thus, we can know that the g-factor for spin angular momentum is equal to 2.
I'm sorry that I'm not good at English.

[atticuskoch]

I just wanted to understand that confusing chart for adding spin, but I got tricked into understanding the fine structure of hydrogen which I had completely given up on lol. Great lecture

[geoffreystuart]

how mixing energy parcels in diferent frames yields correct results

[firemaniac]

Since energy (Hamiltonian) is a frame dependent quantity, how mixing energy parcels in diferent frames yields correct results? Specificaly the h_0 in the proton's center of mass frame and delta_H in the electron's frame!

[avalonrego]

Certain sections in the lecture notes seem to be missing (Chapter 10 section 4, 5 and some part of 6 too i reckon)

[datsmydab-minecraft-and-mo]

15:00 why are we interested in evaluating it at lambda = 0

[lilifathali]

it's excellent!
thank you very much...

[prabhatp]

1:09:05 can somebody give an explanation of what is about to happen?

[Neander]

1:35 you can't mispell Feynman's surname :C

[ahiaamrosi]

In 1:05 why is he saying the l^2 dosent commut with l*s? If we take l*s~(j^2-l^2-s^2) we can see they commut.

[AAAnsie]

This is how I would imagine Benedict Cumberbatch playing a physics professor.

[muhammad.]

can they explain clebsh gordan coefficient

[AdarshKumar-dqwy]

I could not find the lecture notes of this lecture?