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although being graduated in physics (but not being an expert on QED) I find myself embarassed in trying to explain in very simple terms how the electrostatic force arise from the exchange of virtual photon. Especially when it comes to actually reduce all calculations to the expected result F = k q^2/ r^2

Myself I fall in the trap of a lot of complexities about series expansions in term of powers of 1/137, etc. etc. but without being able to sum up all of those fine concepts into a simple formula such as:

F = dp/dt

where:

dp = average momentum exchanged / each virtual photon exchange

1/dt = average number of virtual photon exchanged / unit of time

Considering only the static case, and limiting to the first term (i.e.: single photon exchange), and accepting to sacrifice some of the formal rigour, if it could be possible to obtain simple approximated expressions for dp and dt in terms of 1/r^2 and fine structure constant, that would also help a lot when trying to popularise at least the fundamental concepts.

Oddly, all my efforts to find this in text books have failed.

Is somebody interested in helping to derive such simple approximated expressions for dp and dt ?

Thanks for the help

Luca