I know electrons are identical fermions, but I also think that if two electrons are bounded to the same atom, we can always specify the 4 quantum numbers for each of them, why isnt specifing quantum number a way to distinguish electrons?

Question

osprey · Answer

A good old QM confusion question. in a ground state, a level can be occupied by up to two "identical" electrons if they have opposite spins. Problem seems to be that you can't climb into the QM world (I don't think you can at least ... too small ?) and "see" which electron is which. Applying, say, a magnetic field and getting one of the electrons to flick spin as a result and thus go into a higher energy level "distinguishes" them "sort of", except that there's no QM label that says electron A was the one that flicked, and B didn't. You (I) might try to say that electrons aren't "coloured" - black and white, say. So, that makes them indistinguishable. OK, I've got my shoelaces in a tangle here ... that happens to me when I delve into QM and/or into Spec Rel, or physics in general actually. Part of the (masochistic ?) "fun" ? http://perendis.webs.com

osprey · Answer

Maybe part of the answer to untangling my shoe laces is that if the electrons WERE black and white, then when one of them flicked they'd be "even more distinguishable". 
I'm trying to get the word "degeneracy" into one of these posts ... and I can't do it at the moment.