system
Given the following post, respond as if you're commenting on Reddit:
human
Are there wavelength limits for electromagnetic waves?

This may be interpreted as a Quantum Mechanics question. I recently learned about selection rules for decay of excited states in Hydrogen, which can govern what wavelength/frequency of light is emitted by an electron decaying to a ground state. Since matter that is moving at some velocity can be described as a wave (via its de Broglie wavelength) by lambda = h/momentum, is it possible to generate a photon for any wavelength for that corresponding "matter wave". For example, is it possible to generate a photon with a wavelength equivalent to me travelling at 1 m/s? l=h/(100kg*1m/s) ~ 6x10^-36 m.   Are these waves related to the type of matter that emits them and if so, is that band structure even possible? I know that black holes can emit pretty short wavelengths, but I have no idea if they can emit ones that are that short. Thanks!
gpt
Not really, what happens is that electromagnetism is not valid up to every energy scale. The shorter the wave-length, the bigger is the energy of your photon. Once your photon has an energy comparable to the electro-weak scale, the effects of the unification of EM and weak forces kick in, and it stops making sense talking about a photon.

Nevertheless, you will still have a particle (it just won't be a photon) with that very short wave-length. Once you go to really high energies (or short wave-lengths), the effective description of what's in there changes. This goes up to the Planck scale, where it stops making sense talking about particles localized within that scale, since you start producing black-holes that grow with the energy.