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Double slit experiment, observer effect

  1. Feb 28, 2010 #1
    It was a good while ago since I heard about this particular experiment, but I remember vaguely reading about how in one instance they recorded the observations, but then deleted the data before anyone could look at it, and in that instance the wave was still produced. Thus showing that it really was the act of observing that caused the wave collapse.

    Was this bull? Or can someone direct me to a link?
  2. jcsd
  3. Feb 28, 2010 #2


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    I believe what you are referring to is a Quantum Eraser. If so, this is not a good characterization. A more realistic description is as follows:

    An observation is made, but the system is returned to the state before the observation was made. In so doing, there is no possibility of learning the outcome of the original observation. In such case, the system can continue to exhibit whatever behavior would have been expected prior to the observation.

    The above is real. But you cannot "delete" the information in the sense of data on a disk drive. The process of "erasing" is very specific, and must not leave the possibility of learning the outcome of the original observation.
  4. Mar 1, 2010 #3
    Thanks, that clears up a lot.
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