I apologize if this question was here once before, but i never found an answer that truly satisfy me.
Every electric charged particle is coupled to the photon field which causes them to generate virtual photons with specific momenta that can be accepted by other charged particles, resulting in electromagnetic force.
However, the virtual photons seems to have not an arbitary momentum. In like charges they carry a momentum that is always pointing away from the particle that created the virtual photon. In opposite charges, the momentum is pointing towards the particle. Why this two kinds of possible momenta exist, if positive and negative charge couple both to the same field. What mechanism causes the experience of this two coupling mechanism for the two charges.
Ive read that odd spin bosons always discriminates between two kind of charges and that this is also the case for electromagnetism. Explanations typical ends there and my mathematical understanding is too bad to get an satisfying answer.
