Since frequency indicates certain periodicity in time and space in the wave theory of light, what kind of periodicity do we have in the case of photons as particles?
Again, you’re mixing the wave and particle picture. I would not try and relate the periodicity of the wave to that of a photon. A photon is a quantum-mechanical object, and only has a probability amplitude associated with it. > My impression is that in modern physics frequency is explained as a wave property, and left at that. But the energy of photons in the particle view of light is expressed by hf, where f is frequency, indicating certain periodicity. We need to define what is frequency in the particle theory of photons and how it differs from or corresponds to frequency in the wave theory of light, both occurring in time and space. > For the purpose of clarity and simplicity, we have to start win a single oscillator, like an electron of a hydrogen atom continuously emitting photons of light of the same wavelength. Obviously, this electron can emit only one photon at a time. These photons fall on a frequency detector, which gives us a certain number indicating certain periodicity. W
