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Can double slit interference be explained by the influence of previous photons?

  1. Aug 28, 2012 #1
    The usual interpretation of the double slit experiment, when done with a single photon at a time, is that the photon must interfere with itself. However interference cannot be measured in a single-photon experiment - it requires a large number of photons to manifest a discernible interference pattern.

    Suppose that each photon leaves a kind of "wake" in its path which persists over time, and it is the cumulative effect of these "wakes" which results in the observed interference pattern.

    Might it be that the path of a given photon is influenced by the paths of the photons which have gone before it?
  2. jcsd
  3. Aug 28, 2012 #2


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    You can disassemble the whole setup, displace and rebuild it for every single photon, and you would still see an interference pattern after a while. I would be surprised to see this as actual experiment, but it would be possible.

    How do you tell the wake where in spacetime it should be? In which reference frame should it remain stationary? In the lab, moving around the earth, with the earth moving around the sun and so on all the time? That looks quite arbitrary.

    If the first photon would not behave as expected, you would see it in very improbable regions more often.
  4. Aug 28, 2012 #3


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    Well, if there is a hypothetical "wake": how is it that the interference appears or disappears only according to whether or not the which slit information is available - and has NOTHING to do with any wake?

    And if there is a wake: what kind of wake do electrons, neutrons, molecules and other particles have? These also exhibit double slit interference.

    If you hypothesize a new effect to solve one problem, it usually creates a lot MORE problems fitting in with existing theory. So be careful of ad hoc ideas like this.

    By the way: Welcome to PhysicsForums, patfada!
  5. Aug 28, 2012 #4
    Patfada, welcome to the forum.

    you can wait for a longer time interval between each photon....say 1 hour/day/month/year....you would still get an interference patter, after say, an year or more
    Last edited: Aug 28, 2012
  6. Aug 29, 2012 #5
    Thanks everyone for the responses.

    I wonder what the record is for the slowest double-slit experiment? Has anyone actually seriously looked for a change in the observed interference pattern as the interval between photons is increased?
  7. Aug 29, 2012 #6
    I found a related thread:


    which references the paper AIP Conf. Proc. 810 (2006), 360 by Ghenadie N. Mardari:

    I'll attempt to read it but I doubt it will make much sense to me.

    Thanks again for your responses
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