The clack of two billiard balls signifies the transference of their momentum and the mathematics of resulting vectors is fairly straight forward. At the quantum level, I understand that the transfer of momentum is carried out by photon interactions. This would mean a lot of photons interacting and somehow, in sum, conserving of the classical momentum vectors. If there are no red flags in the above, I would appreciate guidance to a reference that explains the process in more detail, particularly the conservation of momentum. I would guess that each photon interaction must somehow convey vector information. Thanks for your help.

The clack of two billiard balls signifies the transference of their momentum and the mathematics of resulting vectors is fairly straight forward. At the quantum level, I understand that the transfer of momentum is carried out by photon interactions. This would mean a lot of photons interacting and somehow, in sum, conserving of the classical momentum vectors. If there are no red flags in the above, I would appreciate guidance to a reference that explains the process in more detail, particularly the conservation of momentum. I would guess that each photon interaction must somehow convey vector information.