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Modified 2 slot experiment

  1. Mar 31, 2013 #1
    In the 2 slot experiment, I always see the slots side by side. The electron seems to know if the second slot is open or not. How do we know that this would happen even if the second slot was on the moon? Secondly if the slots were placed at the apex of two sharp V shaped walls with the V's pointing towards the final screen. The final screen forms a full circle and the V's are placed in the center facing 190 degrees from each other. The interference patterns should still be able to reach other. If both slots are open and if the electron splits and goes thru both slots then, the electron would have to know that both slots were open at the exact instance it was fired. Rather then splitting as if in a Y pattern, it would have to completely split opposing each others direction. I'm just trying to see if there is any sort of limitation to this experiment and would like to get some input.

  2. jcsd
  3. Mar 31, 2013 #2
    Well, it wouldn't really happen if the other slit were far away (since the motion of the moon is complicated, lets just assume that we have the normal set up, but the separation between the two slits is 10 miles or some other large distance). Theoretically, there would still be some interference, but it is unlikely that it would be strong enough to see it. Lets assume first that the electron is being fired directly at one of the slits. So the set up is slit A with electron being fired toward it from a point a small distance from the wall and aligned so that a perpendicular line between the source and the wall would pass through slit A. Slit B is a much greater distance from the source. Due to this fact, the calculated probabilities for finding an electron near B is far less than that of finding the electron near A. There is technically interference, but it is probably not measurable. If the source were placed equidistant to both slits, the number of electrons being absorbed/reflected by the wall would far outnumber those getting through. If enough get through and are measured, an interference pattern would be seen. In this second case, the distribution see would depend on the exact momentum of the electrons and the distance to the screen and between the slits. But really, there would be other factors that would get in the way and it probably wouldn't work, not due to QM, but due to experimental difficulties.

    Q2: I'm not 100% sure how you see this being set up, but it doesn't really matter. The exact pattern seen would depend on exactly how everything is oriented, but the wavefunction of the electrons would interact. But note: the electron does NOT split. There are not electrons that are splitting up and travelling through multiple slits. You can think about adding up the probabilities of different paths the electron takes, but don't think of the electron actually splitting so that portions of it travel through different slits.
  4. Apr 1, 2013 #3
    My second experiment was having the circular screen completely enclosing a circular wall that has the slots. Like one cylinder inside of another with the emitter being in the very center of the whole thing. In this case, the barrier is two V shaped walls that point in opposite directions (180 degrees) with the bisecting line of the angle of both V's being a common line. OK, I see the electron doesn't split but instead the system depends on the probability of an electron going thru hole B. Being V's wouldn't be any different then just a circular wall. Its just the way I initially pictured it.

    Lets try a few different configurations and convert the wall with the slits to a circular wall so now it is a cylinder within the cylindrical screen and again the emitter is in the center of the two cylinders, (slot wall and screen). In experiment 'A" Lets put the slots again 180 degrees apart in the barrier wall. But is this case lets put 2 second barriers which are also 180 degrees apart with the line connecting them also going thru the center where the emitter is and being perpendicular to a line connecting the two slits. These two barriers run from the outside of the slot barrier wall and continue to the screen effectively creating two separate chambers between the barrier wall and the screen wall. I know that there can't be any interference but would the electrons then act like waves or a particle?

    For setup "B", We will use the same two chamber as above but lets put 4 slots in the barrier being in pairs side by side and each pair being 180 degrees apart with each two slot set going into its own chamber. Then fire electrons thru one slot only. Would the screen then show an interference pattern, one in each chamber.

    For setup "C " lets go back to one chamber and put 3 slots in the circular barrier wall each 120 degrees apart. Here I assume that we would get three interference patterns, one for each pair of slots. In this case I'm looking at the pattern as if we are only getting interference from two wave sets at a time and eliminating the complexity from when all 3 wave sets inter tangle. Would we then get 3 interference patterns on the screen?
    Last edited: Apr 1, 2013
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