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Quantum measurement and prediction

  1. Oct 12, 2005 #1
    Does the process of genuine prediction act most readily through quantum mechanics, as opposed to psychically or psychologically?

    Can observers influence the environment through the action of "quantum prediction" as they do quantum measurement?

    Does quantum prediction rely on the statistics of a quantum wavefunction, resembling the possibilities inherent to the Many Worlds interpretation or the infinite dimensionality of Hilbert space states?

    Can quantum prediction effect macroscopic self-fulfilling prophesy through the correspondence principle?

    Is accurate quantum prediction much more common than classical prediction?

    Please forgive my difficulty in responding.
  2. jcsd
  3. Oct 14, 2005 #2
    Hmm, I'm not sure what you mean by this question. The answer is that the wavefunction is necessary for all prediction in QM, because that's how it is defined. I have no idea what it means to resemble a Hilbert space. The mathematics takes place in a Hilbert space, rather than resembling it. I'm also not sure what is meant by resembling the possibilities inherent to many world interpretation. The MWI is an interpretation; what does it mean to say the thing you are interpreting resembles your interpretation? Am I reading your question wrong?

    I'm a little confused here as well, however I think the answer is simply no. The correspondence principle requires many measurements to operate.

    I don't know. Do you mean that, if we were able to add up every time a QM prediction was accurately made by someone and every time a classical prediction was made by someone, one would be more than the other? Or do you mean something else - for instance, maybe you are asking if QM is more reliable than classical predictions?

    Sorry if I asked more questions than I answered.
  4. Oct 14, 2005 #3


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    If you observe a quantum system with some Hilbert space of states (it need not necessarily be infinite dimensional), the states are projected onto a "spectrum" which among other things gives the probabilities of different possible outcomes of your observation. As these probabilities are not in general equal, some outcomes are more probable than others, and in particular experimental situations you can make good predictions of what will happen.

    This is because in an experiment you can constrain what outcomes are possible at all, and reduce the spectrum to a few choices. In this sense you can use quantum mechanics to make predictions. But note that you had to build this ability into your experiment in the first place. This is akin to the "preparation" of the system for observation that Bohr laid so much stress on.
  5. Oct 15, 2005 #4
    with respect, selfAdjoint, does this really tell us anything? .....(probabilities are not equal = some outcomes are more probable than others)?
    again with respect I think this should read "you can make good predictions of what is most likely to happen"..... but again does this really tell us anything?
  6. Oct 15, 2005 #5
    What is "genuine prediction" please?

    What is "quantum prediction" please?

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