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The Many-Worlds Interpretation: how far does it go?

  1. Jul 4, 2013 #1
    The Schrodinger's cat thought experiment provides two possible outcomes in the many worlds interpretation; it is dead in one universe, and alive in the other. There are however many other possibilities of what could happen; there are wave functions concerning the positions which the cat may occupy. The cat could be lying down 3cm away from the left side of the box, or 4cm from the right side. Measurements like these show that there are an infinite amount of possibilities, especially when we think about it to an atomic level.

    In this theory, does the universe replicate to accommodate each and every one of the possibilities, even at the atomic level?

    Further more, since we have so many possibilities of what may happen in every single action ever made, are there also universes which have a different combinations of the possibilities made?
     
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  3. Jul 4, 2013 #2

    phinds

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    WAY beyond reason, if you ask me :smile:
     
  4. Jul 4, 2013 #3

    bhobba

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    Yes and yes.

    Now you understand why people balk at it.

    But you also need to understand it, from the viewpoint of the formalism, its unbelievably beautiful. Before I started delving a bit deeper into it I simply thought along the lines of how can such a radical view be correct and those that were embracing it resorted to mysticism. But now I know its beauty I understand much better its appeal. Aside from its weirdness its everything you could want. Its deterministic, no measurement problem, no collapse - there are even arguments that explain the randomness from the determinism - everything is beautiful and neat.

    Personally I still cant stomach it, but it has many many positives.

    Thanks
    Bill
     
  5. Jul 4, 2013 #4

    mfb

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    It is important to highlight that there is no explicit "replication mechanism" - it just happens naturally from the evolution of the quantum-mechanical wave function.
     
  6. Jul 4, 2013 #5

    Can you recommend any good secondary sources which which deal with the aspects of many words theories you describe?
     
  7. Jul 4, 2013 #6

    bhobba

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    Most definitely.

    The book I am studying on it at the moment:
    http://users.ox.ac.uk/~mert0130/books-emergent.shtml [Broken]

    Watch it though. It's written by a philosopher but a rather interesting one - he also, aside from professional qualifications in philosophy, has a Phd in Quantum Physics. Because of that he, correctly, doesn't shy away from the math.

    You may need to get a bit of guidance from people on this forum on the background necessary to understand it. The payoff is you will get a much better and deeper understanding than the rubbish often found in the popular press. So get a copy and post about what you are finding difficulty with. It will be a journey you will not complete overnight - but rest assured you can complete it.

    Thanks
    Bill
     
    Last edited by a moderator: May 6, 2017
  8. Jul 5, 2013 #7

    Demystifier

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    As bhobba already said, yes and yes.
     
  9. Jul 5, 2013 #8

    Demystifier

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    It should be stressed that these arguments are considered highly controversial. This and problem
    https://www.physicsforums.com/blog.php?b=4289 [Broken]
    are widely considered to be the two main problems with many worlds.
     
    Last edited by a moderator: May 6, 2017
  10. Jul 5, 2013 #9
     
  11. Jul 5, 2013 #10

    mfb

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    There is not an infinite amount, and you can find the answer to that question in my previous post (#4): the splitting process is a natural consequence of quantum mechanics. There is nothing additional going on.
     
  12. Jul 5, 2013 #11

    Highly controversial. Not even David Wallace would go that far and see Demyst's post
     
  13. Jul 6, 2013 #12
    Bit easier on the eye

    This is possibly my fave book of all time. However, David Wallace also provides the following self-contained, easier-to-read and more to-the-point (for a newcomer to the debates) papers:

    http://philsci-archive.pitt.edu/8888/

    A good place to start, albeit Wallace assumes some familiarity with the measurement problem literature

    http://philsci-archive.pitt.edu/8892/

    More aimed at philosophers than physicists, but a nice read with good overview
     
    Last edited by a moderator: May 6, 2017
  14. Jul 6, 2013 #13
    PS The links i gave above are to preprints. I'm aware of Forum rules re eligible journals, but I'm not aware if any rules apply to preprints. Mods - some guidance?
     
  15. Jul 7, 2013 #14
    Imagine....
    every branch can split to a Graham's number exponential of branchs, in turn, any split of that branch split again to a Graham exponential and so on and so on.......
    per secula seculorum.......




    .
     
  16. Jul 8, 2013 #15

    bhobba

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    Indeed they are - but the reference I gave lays it all bare. Nothing like knowing the detail to make up your own mind.

    Thanks
    Bill
     
  17. Jul 8, 2013 #16

    bhobba

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    David Wallice indeed goes that far. People can make up their own mind about it knowing the detail. My view is there are issues, but will reserve my final opinion until I have gone through his book.

    Thanks
    Bill
     
  18. Jul 8, 2013 #17

    bhobba

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    In the MWI it doesn't have to know - but you need the detail of the theory to understand why.

    And what Demysterfyer mentions is part of the controversy eg the well known factoring problem. Again you need to understand the detail to know whats going on. And also be aware not everyone believes the factoring problem is a problem. For example Schlosshauer doesn't even mention it in his book on Decohrerence and I did manage do dig up a paper where from a simplified model it was shown to not be an issue. IMHO more research needs to be done.

    It has been thrashed out in quite a few threads, you just need to do a bit of a search.

    Thanks
    Bill
     
    Last edited: Jul 8, 2013
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