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Homework Help: A quick(?) question about the Pauli exclusion principle

  1. Nov 20, 2009 #1
    This might be an ignorant question but I have to ask it. The exclusion principle forbids particles from existing with the same quantum numbers, like, if you had 2 electrons, they have quantum numbers n, l, ml and ms, and one out of those 4 has to be different, right?

    What I was wondering was how close do two particles have to be before the exclusion principle starts working?
    obviously two electrons in different atoms can have all the same quantum numbers, but I ask this because I'm reading about quarks in baryons, and apparently they violate the principle, so how come they can get close enough to each other to be in the same particle?

    I get the feeling theres something huge here that I don't quite understand yet.
  2. jcsd
  3. Nov 20, 2009 #2


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    Hi jeebs! :smile:
    "close"? … I think you're thinking of free particles.

    Particles such as electrons round an atom are in the same ball-game, and it only has certain available quantum numbers …

    it doesn't matter how "close" two electrons are (eg are they on opposite sides of the atom?): what matters is their orbits, not their instantaneous positions.
    They have to be different "colours", and "colour" is a quantum number. :wink:
  4. Nov 21, 2009 #3
    I believe the apparent violation of the exculsion principle was used to show that another quantum number (dubbed colour) exists.
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