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How does one fermion change the energy of another fermion

  1. Aug 18, 2013 #1
    My understanding of how one fermion changes the energy of another is something like: fermion x approaches fermion y and x emits bosons which are absorbed by y. But why does one billiard ball transfer a lot of its energy to another billiard ball on contact? Say billiard ball x approaches billiard ball y, x hits y, x stops and y moves. I realize the Pauli Exclusion Principle forbids x from occupying the same place as y. But why does y absorb more bosons from x than vice versa? Why would the fact that x is moving y to absorb more bosons from x than x absorbs from y?
  2. jcsd
  3. Aug 18, 2013 #2


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    hi susskind99! :smile:
    sorry, but that's just a myth told by mathematicians to frighten physicists! o:)

    those boson lines you see in feynman diagrams "carrying the force" are just a mathematical trick that help in the calculations

    after all, when two electrons repel each other, do you think that can be explained by by emitting (presumably negative-mass) bosons? :wink:

    (and btw, it's really the momentum that's affected, rather than the energy)
  4. Aug 18, 2013 #3

    Then how does a fermion's energy change?
  5. Aug 19, 2013 #4
    Like kinetic energy? You can accelerate a charged fermion via electric field.

    Or you mean increase of electron energy in atomic orbital? Electron absorbs a real photon.
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