I haven't taken any course in quantum field theory or read any advanced books about it, but I would like to make what I think is a deduction. An electric field can be explained by changing magnetic field. Provided that some property of this changing magnetic field was met, the electric field may correspond to the electric field produced by a subatomic particle. So far, I don't know of any other type of field that would generate an electric field other than a changing magnetic field. Do the quantum physicists explain the electric field of subatomic particles this way? Do they know the changing magnetic field that would be necesary to generate the electric potential of the proton for instance?