Ampere's law with quantum mechanics

[exmarine]

Ampere’s law – parallel electrical currents attract – has been known for a long time. How is that understood or explained in quantum mechanics?

 

[lugita15]

The attractive force between parallel currents is the magnetic force. The magnetic force exists so that the electric force comports with special relativity: if the electric force existed on its own, then the force on a particle wouldn't transform right from one inertial frame to the other. So now the question becomes why does the electric force exist? The electric force is due to the exchange of photons between charged particles.

P.S. We can go further down the rabbit hole. Why is there a coupling between charged particles and photons in the first place? At some point in physics it's safer to say "Beats me."

 

[DarioC]

If you want to really get into this you might Google "Quantum electrodynamics."
Wiki is the first reference I got there and will give you a bunch of information that might make your head hurt, but working backward and forward from the information there may be enlightening.
DC