How can we consider static electromagnetic field in QFT point of view?

[ndung200790]

Hi everybody!
Please explain to me how can we consider static electromagnetic field in point of view of Quantum Field Theory.Because varying electromagnetic field can quantize to photons,so we can consider varying electromagnetic field like a ''set'' of photons.
Thanks very much in advance.

 

[Lapidus]

Hi everybody!
Please explain to me how can we consider static electromagnetic field in point of view of Quantum Field Theory.Because varying electromagnetic field can quantize to photons,so we can consider varying electromagnetic field like a ''set'' of photons.
Thanks very much in advance.

Short answer, I guess, is that the static field in qft is the classical static field plus some "quantum corrections". That means that when you use perturbation theory to calculate the energy between some charges, you get the classical em potential result at first order and then some minor corrections to that at higher orders.