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QED Feynman (coupling number called j)

  1. Nov 10, 2006 #1
    On page 92 (Figure 58) Feynman states:
    "The amplitude for a coupling is a number that I will call j; it is about
    negative .1 for the electron (this number is sometimes called the "charge").
    Charge?? I don't get it.
    Would appreciate an explanation?
  2. jcsd
  3. Nov 11, 2006 #2

    Meir Achuz

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    In what is called "natural units" in QED, the charge on the electron is given by e^2=1/137, so e would be about .1.
    If you want to put in units, you would have e^2/(hbar c)=1/137.
    You could even put in 1/fourpiepsilonzero if you want.
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