Reading the FAQ on how phonons

[xiankai]

after reading the FAQ on how phonons, or modes of vibrations, are responsible for the slowing down of photons in dense materials, i still have some unanswered questions:

i visualise phonons as something like qualities of a field, because they coordinate the deviant behavior of individual particles.

ultimately, is it the particles that absorb and re-emit the photons with the observed characteristics of phonons,

or is it that the phonons are something like gravitational waves (ONLY in the sense that they cannot be directly observed, but their effects are documented); an invisible field that coheres the movement of the photons, such that the actions of individual particles are ignored, but are observed as a 'single entity'

thanksie

 

[inha]

phonons can be directly observed. one can measure phonon dispersion relations with inelastic neutron or x-ray scattering. so although they are collective excitations of the whole many body system they are real in that sense.