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Is predicting the future with Quantum Erasure possible?

  1. Mar 18, 2013 #1
    Hi I tried to post this before but it got messed up. hopefully it doesn't post twice. I'm new to this forum and signed up just to ask this question. I have just read this website and it has helped me to understand the basic problems of quantum mechanics. After thinking about the quantum erasure experiment described at the end of the site I thought of my own experiment where it would possible to predict any one future event of your choosing. I thought I must be wrong but I cant find any information to answer my question so I'm bringing it to you. So here is the experiment...

    You modify the erasure experiment so that path of the p photon now has 3 paths instead of one definite one and a switch that can decide the path taken by the photon. The first path is a loop that can hold the photon indefinitely. It could be something like a fiber optic loop or two mirrors facing each other. I don't know. Whatever it has to be to make this work. So everytime the photon makes a revolution around this loop the switch can then decide weather or not it wants to send this entangled photon back to the loop again, down the second path, or down the third. The second path leads to a polarizer and then to a detector like in the erasure experiment and the third path leads to just the detector bypassing the polarizer. If you look at the pattern that s photon produces won't that tell you which path that p photon eventually went down? or basically weather or not it bothered to go through erasure process?

    For instance I build a machine that is tied to the switch. The machine is programmed so that if the Browns win the superbowl in the future it switches the path of p photon to the polarizer and if they lose it bypasses the polarizer and goes straight to the detector. Now by weather or not I see and interference pattern from s photon I can then know which path the p photon will go and hence weather or not the browns will win the super bowl.

    Am I way off base here? This is kind of a troubling thought. Any answers would be great. Thanks.
  2. jcsd
  3. Mar 18, 2013 #2


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    No, the s-photon pattern never changes, irrespective of what you do. you will find all the interesting patterns only in the coincidence counts between the detectors for the p and s photons.

    Therefore, you may find some interesting pattern in the coincidence counts between the detector detecting the s photon and the detector in p-photon path 2 and you may find another interesting pattern in the coincidence counts between the detector detecting the s-photon and the detector in p-photon path 3, but the pattern of s alone will be the same in all these cases.
  4. Mar 18, 2013 #3
    i see. I guess i don't understand the coincidence counter part well enough. I'll have to look up a good explanation of it. thanks for your answer. this has been bugging me all weekend.
  5. Mar 19, 2013 #4


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    Thread closed for Moderation...

    Thread will remain closed. User account terminated due to inappropriate username.
    Last edited: Mar 19, 2013
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