L22.4 Identical particles and exchange degeneracy

[@Soni342-i6u]

This is gold!

[@satyamshukla381]

Electron spin up and electron spin down state has same mass. Nucleon spin up and nucleon spin down state has different mass, why to call them same state. Why is there this difference?

[@bilalhussein9730]

Isospin is an approximate symmetry. As you said the symmetry is broken by the nucleon mases and electromagnetism as the proton is charged while the neutron is not. What is meant by an approximate symmetry is that if we get results that are true assuming exact isospin symmetry, then the actual result in nature is the same thing up to percent-level corrections because of the smallness of the fine structure constant and the mass difference between up and down quarks divided by the QCD confinement scale. We can then use techniques like perturbation theory to solve for these corrections.

[@Neo-Reloaded]

Sir, I don't understand the isospin. Can you make a video about that?

[@inonazizi7981]

I'm also a little confused on the isospin

[@cikif]

10:38 We *cannot* do the same

[@nphuc]

"cannot" is a very important word in this situation.

[@bruna.corcino]

Dar um quadro branco pra esse homem. Todo sujo de pó de giz o pobri.

[@hectorfreire4991]

Chamar um professor do MIT de pobre é a melhor parte kkkkkk

[@bluedot6933]

no two things can be identical, there must be some property that distinguishes one from the other. if 2 things a and b have the same properties then those 2 things are in fact one thing.

[@The_Don_Dial_100]

😂 it's not philosophy its physics... 😅 Don't Give unusual Hypothesis

[@bluedot6933]

for everything there must be a sufficient reason for why it is and not different. if identical particles existed then there would be no reason for one to be one and for another to be another. @@The_Don_Dial_100

[@RobbyAndrews-j5k]

Give me a lav and the money to protect my MG theory