I have a question concerning the notion of electric charge in QFT.(adsbygoogle = window.adsbygoogle || []).push({});

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]?

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# Electric charge in quantum field theory

Can you offer guidance or do you also need help?

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