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B Superposition and MWI

  1. Aug 11, 2017 #1
    My question is, "Is superposition necessarily and only related to the time between triggering and observation?" And further on that point, in the MWI theory, as opposed to the Copenhagen interpretation, do quantum particles actually enter and "exist" in a superposed realm before observation? Or do they simultaneously branch out into all possible outcomes creating events in parallel universes at the triggering moment?. In other words, is there any basis for superposition in the MWI. Please be aware that the base level of my understanding is non-mathematical. Albeit logical, whatever that counts for in QM. LOL. Kind regards.
  2. jcsd
  3. Aug 11, 2017 #2
    I just read my lately arrived June 2017 issue of Scientific American now and there is this article called "Quantum Multiverse" the author alleged the Multiverses may be nothing but the Many Worlds of QM.. here's some excerpts to make you interested and buy it:

    "If a quantum state reflects only the region within the horizon, then where is the multiverse, which we thought existed in an eternally inflating infinite space? The answer is that the creation of bubble universes is probabilistic, like any other process in quantum mechanics. Just as a quantum measurement could spawn many different results distinguished by their probability of occurring, inflation could produce many different universes, each with a different probability of coming into being. In other words, the quantum state representing eternally inflating space is a superposition of worlds—or branches—representing different universes, with each of these branches including only the region within its own horizon.
    Because each of these universes is finite, we avoid the problem of predictability that was raised by the prospect of an infinitely large space that encompasses all possible outcomes. The multiple universes in this case do not all exist simultaneously in real space—they coexist only in “probability space,” that is, as possible outcomes of observations made by people living inside each world. Thus, each universe—each possible outcome—retains a specific probability of coming into being.
    This picture unifies the eternally inflating multiverse of cosmology and Everett’s many worlds. Cosmic history then unfolds like this: the multiverse starts from some initial state and evolves into a superposition of many bubble universes. As time passes, the states representing each of these bubbles further branch into more superpositions of states representing the various possible outcomes of “experiments” performed within those universes (these need not be scientific experiments—they can be any physical processes). Eventually the state representing the whole multiverse will thus contain an enormous number of branches, each of which represents a possible world that may arise from the initial state. Quantum-mechanical probabilities therefore determine outcomes in cosmology and in microscopic processes. The multiverse and quantum many worlds are really the same thing; they simply refer to the same phenomenon—superposition—occurring at vastly different scales."

    So be careful of any quantum choices present because each can produce an entire multiverse. I guess this means during period of unrest like World War II, it's better to avoid doing any quantum experiment to avoid creating more duplicate worlds? What is your and others opinion?
  4. Aug 11, 2017 #3


    Staff: Mentor

    Superposition is part of the basic math of QM. As such it appears in all interpretations, including the MWI, since they all use the same basic math.

    It's really hard to properly understand the concept of superposition without some math. At a minimum, you need to understand basic linear algebra and the concept of a Hilbert space and vectors in it. Superposition then just corresponds to the fact that you can always express any vector as a linear combination of other vectors.
  5. Aug 12, 2017 #4
    - but we could just as well consider all the conceivable multiverse(s) already existing - as the Potentiality - from the very beginning; and every quantum choice killing most of the universes (those which failed to get actual), rather than producing. That would be according to Heisenberg (and Oppenheimer: "I am become Death, the destroyer of worlds.":smile:)
  6. Aug 12, 2017 #5
    Right now with all the turmoil in the world.. i'm avoiding any quantum devices.. whenever I see slits especially double.. I get nervous and make sure the electronics behind it is turned off to avoid accidental creation of more worlds where it can only create more turmoil...
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