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Delayed Erasure follow-up experiments

  1. Apr 6, 2015 #1
    does the double slit experiment with the Delayed Erasure follow-up experiments prove that objective reality does not exist ? How is it possible to detect the particle without affecting it?
    My understanding up until now has been that the results differ with/without a measurement because the measurement process necessarily changes what is being measured.

    Based on this video: watch?v=sQfSm6o-KlQ

    QUESTIONS:
    1.
    There can be no measurement without a conscious observer.. The conscious observer may not be monitoring M1 at the time of a particular experiment, as in this example, but It requires a conscious observer which has measured the results of the experiment (i.e. looked at the screen an noticed there was no interference)...Therefore the right side experiment does include an observer, otherwise it would remain in a superimposed (unknown) state. The right side, if no observer has observed the result, is in a superimposed state of both having interference and no interference...Otherwise there is no experiment. Delayed Choice Quantum Erasure shows us that it is indeed not consciousness that directly collapses the wave function, but rather, it is the KNOWLEDGE that is perceived within consciousness that has this effect ?

    2. If machine M1 makes a measurement, but then erases the data, then interference pattern appears. explain that one..

    3. Here is another question, what does M1 use to measure position. If its a photon and it not hitting something like photo paper leaving a mark then isn't M1 using some sort of wave or force to measure change? M1 is like the detectors near the slit in the observation that changes waves to particles. These two forms of detectors don't stop the partial they use an electromagnetic wave to measure it. Also if they are forced to choose either wave or particle because according to superposition they are in both why when observed do they always choose particle. If a detector uses a force or a wave to measure change then it interferes with the physical state of the object. Unlike M2 which observes the focal point of the waves furthest edge or the particles impact point after being altered by passing through the slit and any present detector. The particles are no longer traveling past M2 they are being marked as present at a given point they have already reached just like the detectors located at the slit are only showing the photons are present or not at their slit at that time. What is M2 using to detect partials is it more like the photo paper suggested showing impact via a chemical dye or loss of pigmentation due to impact of the energy in photons wave or particle or is it a device measuring force as an object passes like M1 seems to.
    Can the same thing be said be said for the human eye which takes in the photons or waves but is not sending them out. So do an experiment if a human stares at the double slit while the photons wave or particle goes through the double slit what kind of pattern to you see. If no one is looking at the double slit does the same pattern appear or is it only when you use some sort of detector that physically uses stronger forces (for example electro-magnetism) to as we say detect smaller particles that we assume we are not seeing. We assume this because we are not sensitive enough to them or rather are we seeing them but they are two small to be amplified to visible size outside of the vast background noise of many photons and other particles we are already observing. It takes a pattern of or many instances of the same kind of particle doing the same thing to be observed by the human eye. The Quarter Wave Plates what are they using to measure and change the polarization of photons an do they change the pattern observed on M2 from wave to particle or the other way around?

    There are some papers that support this view:
    http://arxiv.org/abs/quant-ph/0103043
    http://arxiv.org/abs/quantph/9905054
     
    Last edited: Apr 6, 2015
  2. jcsd
  3. Apr 6, 2015 #2

    bhobba

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    Gold Member

    Of course not. QM is ambivalent to such - interpretations all have a different take - and many are ambivalent to it. What it shows is deoherence in simple cases is reversible.

    Yes - you have to interact with it. So?

    Unless you observe something you don't get an observational outcome. Nothing mysterious there.

    QM is a theory about observations that appear in an assumed common-sense classical macro-world. No concious observer required. The issue here is how a theory that assumes such a world explains it. A lot of progress has been made in resolving it - but a few issues remain.

    Regarding those papers Stapp is a well known proponent of the those type of new age conciousness is involved views of QM. The fact of the matter is it simply isn't required. It was introduced by Von Neumann for reasons that were later found to be misunderstood. It attracted very little support even then, but one was Wigner. Von Neumann died young but when Wigner saw some early papers on decoherence by Zurek realized the reasons for its introduction were no longer valid and did a 180% turn around and advocated objective collapse theories.

    Thanks
    Bill
     
  4. Apr 6, 2015 #3

    Nugatory

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    Staff: Mentor

    The video link you posted is broken, so there's no way of knowing whether you are misunderstanding the video or whether it is misleading/wrong, but your questions suggest that it's not doing a very good job of explaining the delayed choice quantum eraser. There's a pretty decent but still user-friendly description of the most solid version of the experiment here which you may want to read. Look especially at the role of the coincidence counter in that experiment - the interference pattern does not appear and disappear, and indeed it is not projected on a screen at all.
     
  5. Apr 6, 2015 #4
    I believe the video referred to is
     
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