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A Thought Experiment: Photons Passing through Detectors

  1. Sep 19, 2015 #1
    mulsi5.gif

    Pretend we have a multi-slitted grating whose slits are infinitesimally small. We On each slit is a detector. If we shine (UPDATE) [strike]light[/strike] monochromatic light through the grating, what distribution pattern occurs on the screen past the grating?

    I understand the train of thought to a slight variation of the preceding scenario. In this alternate scenario, instead of multiple photons passing through the slits simultaneously ( i.e. light shining through), photons pass through the grating one at a time. Here, the photons won't give rise to the familiar distribution pattern shown in the image. While each passing photon would normally interfere with itself (we can't definitively know the photon's position, so we take its trajectory to be the combination of pathways through each slit -- and hence, it's as if mutliple photons were entering simultaneously), by putting a detector in place, we localize its position and destroy the intereference distribution.

    If this reasoning is true, I can't extend it to the scenario I want to resolve. In this scenario, while the interference pattern arising from the passage of any one photon is destroyed, does not the interference pattern arising from the passage of multiple, distinct photons remain?

    Hence, should not the pattern be shown?
     

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    Last edited: Sep 19, 2015
  2. jcsd
  3. Sep 19, 2015 #2

    andrewkirk

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    I think the answer is that, unlike alternative paths for a single photon, distinct photons will not pass through the slits at exactly the same time. There will be a random noise term that is the difference between the phases of two distinct photons at the point they passed the slit. That noise term destroys the interference pattern that would otherwise arise from the fixed difference in path length from the two sits to a given point on the screen.
     
  4. Sep 19, 2015 #3

    mfb

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    If you add the patterns arising from single photons that don't show interference, you get a pattern that doesn't show interference.
     
  5. Sep 19, 2015 #4
    However, can't one photon interfere with another one? Shouldn't we observe an interference pattern from the superimposition of photon wavelengths having different path lengths (i.e. have something close to what's below).

    doubsli.gif
    http://data:image/jpeg;base64,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
     
  6. Sep 19, 2015 #5

    andrewkirk

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    No, because (as noted above) the two photons will pass the slits at different times, so the phase difference on the screen will not be a pure function of y.
     
  7. Sep 19, 2015 #6
    I haven't encountered this in my reading. Can you explain a bit more or perhaps link me? Why would the noise term occur? I should clarify that this thought experiment used monochromatic light -- so wouldn't photons start off in phase?
     
  8. Sep 19, 2015 #7

    andrewkirk

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    Light being monochromatic affects frequency, not phase. Two photons will be out of phase with one another when they encounter the slits because they have been emitted from the source at different times.

    This is not an issue for the interference discussed in treatments of the standard double-slit experiment because they are discussing a photon interfering with itself, and a photon is always in phase with itself when it reaches the slits.
     
  9. Sep 19, 2015 #8
    Ah, so through the double slit experiment and similar ones, interference is never produced as a result of distinct waves superimposing but through photons interfering with themselves. I should take this away, no?
     
  10. Sep 20, 2015 #9

    bhobba

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    I think the following is a much better way of looking at the double slit:
    http://arxiv.org/ftp/quant-ph/papers/0703/0703126.pdf

    Thanks
    Bill
     
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