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Electric charge in quantum field theory

  1. Nov 20, 2011 #1
    I have a question concerning the notion of electric charge in QFT.
    What value of charge for electron should I use if I want to compute
    the force acting on electron in some external electric field. Of course
    in first approximation it is just elementary charge which value might
    be found in
    http://physics.nist.gov/cgi-bin/cuu/Value?e".

    I wonder what value should I use if I wanted to compute the force
    using some vertex corrections from QFT. I'm not asking if this is sensible.
    I only want to understand the concept of charge in QFT. Let's assume
    that the bare charge (the walue which appear in lagrangian) is
    equal [tex] q_b [/tex], the electromagnetic potential renormalization
    constant calculated in given order is equal [tex] Z_3 [/tex] (this constant is chosen
    so that in given order the photon propagator has at [tex] p^2=0[/tex]
    unit residue), elementary unit charge is [tex] e [/tex] and [tex] q [/tex]
    is the value of charge which I should use to compute force acting on electron
    taking into account qft correction.

    Is it true that [tex] q=\sqrt{Z_3} q_b=e [/tex]?
     
    Last edited by a moderator: Apr 26, 2017
  2. jcsd
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