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Question about quantum erasure experiment

  1. May 8, 2015 #1
    I'm not a physicist, but I have a layman understanding of some aspects of Quantum Mechanics. I just watched a video explaining the experiment, where you put two differently polarized sheets behind each slit, but then erase the polarization with third polarizing sheet that's located between the slits and the measuring screen.

    And I wondered, does it make a difference on how far away from the slits you put the third sheet? Like, does the pattern get wider or shorter depending on if you put the erasor closer to the slits or closer to the measuring screen?

    Also, would the outcome change, if the erasor would be so close to the measuring screen, that the distance between them would be shorter than the wavelength of the "particle"?

    Sorry to ask these very basic questions here, but I couldn't find a site where the experiment is not only explained, but where I could also find concrete answers to these questions.
  2. jcsd
  3. May 9, 2015 #2


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    No, as long as the sheet is large enough (otherwise there might be areas you don't cover).
    Then you get nasty near-field effects of polarizers, and the answer depends on details of the setup.
  4. May 9, 2015 #3
    I see. Thank you for the explanation. Much appreciated :)
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