2

If the photon (as a quantum of the electromagnetic field) has no defined(?) amplitude, how does (or where from?) the electromagnetic wave's amplitude appear?

The formulation of the question is not quite precise, but the main idea is if we cannot define the single photon's amplitude, since $E=hf$ only (are there any other equations?), how can we talk about an amplitude of an EM wave, which is carried via photons (EM quanta)?

Danu
  • 16,302
static
  • 181
  • 1
    possible duplicate of What is the relation between electromagnetic wave and photon? – John Rennie May 01 '14 at 13:59
  • The energy of the electromagnetic wave is the sum of the energies of the photons composing it. The classical amplitude is built up from the ensemble of photons consistent with the Maxwell equations . see http://motls.blogspot.com/2011/11/how-classical-fields-particles-emerge.html – anna v May 01 '14 at 15:33
  • @JohnRennie: ok, this one is really good. should I remove the question or just let it so? – static May 01 '14 at 15:33
  • @annav: so the classical amplitude as in the macroworld is nothing but kind of human-level representation of the complexity of the real-world phenomenon? – static May 01 '14 at 15:38
  • Well, it is an emergent phenomenon that is anchored both in the micro world and in the macroscopic world on Maxwell's equations. The classical is built up "lego like but with complicated mathematical contortions" from the quantum mechanical one. In the macroworld we do not need to refer continually to the micro quantized framework, because of the continuity given by the maxwell equations. the classical wave is sufficient for most situations. – anna v May 01 '14 at 15:40
  • @annav: thank you very much for the simplification and parallels/comparison in explanation – static May 01 '14 at 15:50
  • @static: I suspect this question will end up being closed as a duplicate. I would leave the question where it is. You've got an upvote and +5 reputation for it and deleting the question will delete the upvote and +5 reputation as well. – John Rennie May 01 '14 at 15:59
  • @JohnRennie: ok, as well as some additional words in the comments were said related to the question and explanation. – static May 01 '14 at 16:03

0 Answers0