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EM waves vs photons

  1. Mar 28, 2009 #1
    Are there any EM wave behaviors that cannot be explained in a purely physical, "photonic" manner? I'm speaking specifically of the photon's path from emitter to absorber, irrespective of "why" that path was taken (in other words, the double-slit experiment does not qualify in the context of my question). Basically, is the attached picture ever possible?
  2. jcsd
  3. Mar 28, 2009 #2
    That picture looks to me like a representation of a polarized wave going through a polarizing material only if the axis is in the right direction.
  4. Mar 28, 2009 #3
    The picture was an attempt at showing an EM wave doing an "end run" around the edge of an otherwise impenetrable material (a very thin wall, for example). Notice that a photon traveling in a direct path between the emitter and the absorber would not be capable of doing this. Is there evidence that this ever occurs? I'm asking for direct evidence of wave-like behavior.
  5. Mar 28, 2009 #4
    Are you asking, does light ever display behavior that a shower of bullets can't? The answer is yes. Consider diffraction.

    If I remember my history correctly, the Airy disk was predicted mathematically before it was observed experimentally. When it was demonstrated soon thereafter, the corpuscular theory of light was demolished.
  6. Mar 29, 2009 #5
    Cantab: I will look into it, thanks so much. Any other ideas?
  7. Mar 29, 2009 #6


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    Staff: Mentor

    What makes you think photons travel in direct paths, or indeed in any well-defined path at all? :wink:

    Quantum theory doesn't address the question, "which path does a photon (or any other particle) take?" That is the subject of interpretations of quantum theory, about which there is no general agreement.
  8. Mar 29, 2009 #7
    In each case, an EM-wave such as the one you drew is NOT a photon bobbing up and down.
  9. Mar 29, 2009 #8
    jtbell: I find it interesting to assume a fully and objectively realistic world that exists without our involvement. I test my theories by asking questions. Yes, this is the subject of interpretations but, regardless of whether we are unable to ever know the answer, this should not mean that a "true" answer does not exist.

    Nick89: Thanks for helping this non-Physicist but I understand that the photon itself does not "bob". I'm curious to know whether there are circumstances inexplicable by straight-traveling particles (or a "shower of bullets" as Cantab described them).

    I was thinking along the lines of maybe a shadow which was diffracted along its edges, but shadow diffraction occurs on Earth due to molecular scattering from the air. Basically my question could be answered if I knew whether a shadow has a distinct edge in a vacuum. I think. :uhh:
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