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Homework Help: A four potential

  1. Mar 13, 2006 #1
    Hi I need a good example of a four potential that yields a photon
  2. jcsd
  3. Mar 16, 2006 #2
    The gauge field of the EM-interaction.


    edit : let me ask you this question : "Do you know why a quantumfield yielding a photon must be a 4-field ?"
  4. Mar 20, 2006 #3
    of course gauge invariance. The e-m exhibits U(1) gauge invariance. (but feel free to remind me about anything of this)

    A four potential looks like this: a(q) +b(x)i + c(y)j+ d(z)k
    I´m just too lazy to calculate them and have never really done it, but I need to know an example of a(q), b(x), c(y), d(z) for a photon.

  5. Mar 22, 2006 #4
    ok, can´t find the edit button, but of course functions a, b, c, d in the last message depend on more than one variable (perhaps all q, x, y, z).
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