Computational Blackbody Radiation describes radiative energy transfer as a resonance phenomenon between resonators connected by standing electromagnetic waves in a vacuum between the resonators. The acoustic analog is depicted above: Energy is transferred from one tuning fork to another by standing acoustic waves as pressure variations in still air.
In this model the finite speed of electromagnetic (or acoustic) waves only influences the energy transfer in a start up phase, while in a stationary state of standing waves the energy transfer can be viewed to be instantaneous without time delay, or to be without time aspect. The transfer of energy is one-way from hot (high frequency) to cold (low frequency).
In this view there is no need to introduce particles named photons carrying energy packets at finite speed back and forth between the resonators, as if the resonators were connected by a two-way highway with trucks transporting energy in both directions. There is no experimental evidence of the existence of such a two-way stream of light quanta. Einstein introduced light quanta in his annus mirablis 1905, but changed mind before passing away:
- All these fifty years of conscious brooding have brought me no nearer to the answer to the question, 'What are light quanta?' Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken. (Albert Einstein, 1954)
The idea of a photon as an elementary particle acting as force carrier of the electromagnetic force, is a basic element of the standard model. No wonder that physicists are not happy with this model. The photon as carrier of the electromagnetic force like the graviton as carrier of the gravitational force, is probably Einstein's biggest mistake, far bigger than the cosmological fudge constant in Einstein's equations, and a return to the primitive corpuscular theory of light of Thomas Hobbes (1644), which was superseeded by Huygen's wave theory (1678), once Newton was dead, but then surprisingly popped up again in Einstein's 1905 article on the photoelectric effect.