[CamperBob2]

Quarks don't have quantum energy states to transition between, hence they aren't subject to radiating photons due to acceleration.

Similar to why the electron in a hydrogen atom doesn't keep emitting radiation and crash into the nucleus once it reaches its ground state... there's no lower state for it to jump to.

[Jblx2]

Electrons in an antenna aren't transitioning between quantum states and are still radiating.

[DHRicoF]

Yes they are. They are transitioning through levels in the conduction band where you have plenty of them.

Every time you see a macroscopic phenomena, you are looking at a stupidly high amount of quantum levels with very similar energies.

[CamperBob2]

That's a good point, I don't know what's up with that. Google just says, "A single oscillating electron does not continuously emit radio waves; it has a microscopic probability of emitting a single RF photon during a given cycle." It would be necessary to delve into the whole QED thing to get a better explanation, based on what I'm reading.

Either way, quarks don't have an electron-like magnetic moment, so they aren't capable of coupling to the EM field.