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Can't The Collapse of The Wave Function be Explained Without MWI?

  1. Sep 28, 2010 #1
    Okay, so I am no expert in this field, but would like to acquaint myself more with quantum mechanics. As I understand it, the collapse of the wave function according to MWI only appears to occur, when really the observer is copied into as many different histories or worlds as there are possible outcomes for the event, therefore seeing only one and wondering why. Also as far as I know, worlds only "split" when a thermodynamically irreversible event occurs. But what I am asking is can't the wave function collapse be real and not just apparent? Can't the wave function collapse be due to an interference and not involve going beyond internal causation?

    I would be very happy if you could shed some light on my question. Thank you.
  2. jcsd
  3. Sep 28, 2010 #2
    You see, it all depends on what you mean by "real". Because it seems that the wave function does not have the same reality status as chairs and tables.
    But if you ask whether it can be considered as an objective rather than subjective event, then the answer is "yes". It can. There are physicists who consider it as such, though there are also other physicists who disagree. You do not have to split the universe to collapse the wave function. And you do not have to split your mind. Simple objective collapse models are being used for instance in quantum optics. To quote from http://www.gap-optique.unige.ch/Publications/PDF/PenroseDiosi.pdf" [Broken] by D. Salart, A. Baas, J.A.W. van Houwelingen, N. Gisin, and H. Zbinden, Group of Applied Physics, University of Geneva, PRL 100, 220404 (2008)

    "When is a quantum measurement finished? Quantum theory has no definite answer to this seemingly innocent question and this leads to the quantum measurement problem. Various interpretations of quantum physics suggest opposite views. Some state that a quantum measurement is over as soon as the result is secured in a classical system, though without a precise characterization of classical systems. Decoherence claims that the measurement is finished once the information is in the environment, requiring a near cut between system and environment and arguments assuring that the system and environment will never recohere. Others claim that it is never over, leading to the many worlds interpretation [1]. Note that none describe how a single event eventually happens. And there are more interpretations and many variations on each theme. In practice this measurement problem has not yet led to experimental tests, though progress in quantum technologies bring us readily closer to such highly desirable tests [2].
    Another possibility, supported among others by Penrose [3] and Diosi [4] (see also the useful review [5]), assumes a connection between quantum measurements and gravity."​

    There are also other possibilities.
    Last edited by a moderator: May 4, 2017
  4. Nov 6, 2010 #3
    The MWI is a MMI and QM is not complete because it requires explanation and th e interpretations are explanations. Also, if something is different it involves something else being different, which involves something else being different, and so on indefinitely in the same universe. Does MW fit with this? Also, how do we know all these supposed possibilities are really possibilities? And how do we know th e superpositions apply in th e macrocosm. In the Schrodinger's Cat case, th e cat would be observing itself so there would be no paradox. As well, how can there be dead universes if there is no one to observe anything in them?

    I'm not saying MW is wrong but it does raise some questions.
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