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B Double slit experiment for layman

  1. Jan 4, 2017 #1


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    In the literature we are told that the double slit experiment works but are given no description of the experiment apparatus
    How big are the slits, how far apart are they, or does it matter
    Would using 3 slits make a difference, would photon go through A and B, or through B and C, or all 3.
    When going through 2 slits is the photon energy halved or doubled., or the same. That would have me scratching my head.
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  3. Jan 4, 2017 #2


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  4. Jan 4, 2017 #3


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    If you google for "practical double-slit experiment" you will find a number of good descriptions.
    Don't be thinking as if the particle is going through both slits (or all three, in a triple-slit experiment). You'll hear it described that way in some popularizations, but that model is very misleading.

    What's really going on: We calculate the probability of the particle landing at any point on the screen by summing the probability amplitudes for every possible path between the source and the screen. If there are two slits, there are two possible paths. If there are three slits, there are three possible paths... and so on. But this calculation isn't saying anything about which path the particle follows and it certainly isn't saying that the particle divides into pieces and goes through more than one path.

    (If we put a detector in one of the slits, then we know to not count the path through that slit if the detector doesn't trigger, and to count only that path if it does trigger. But the general principle is the same - we're adding the probability amplitudes for all the possible paths between the source and the screen).
    Last edited: Jan 4, 2017
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