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Quantum Physics and Parallel Universes and your mind

  1. Jul 6, 2009 #1
    Hello everyone. Im new here so let me say what I said in my first post first...

    Hello everyone, before I start, I just want to say I’m a little out of place here. I am not a student of physics or cosmology, and I am definitely not a professional at anything scientific. I am an artist and going to school for Industrial design. I have always been fascinated with Science, and understand it, but lack the mathematical ability to pursue any scientific field, I just have a talent for creativity and a mostly A.D.D. wired brain...I do have some thoughts though on physics I want to share with people and ask questions and all, but I don’t have anyone to really talk about it with. Most people get lost when I start talking about these things so hopefully you guys can help me more on this, and even though I might not know much mathematically, I hope maybe creatively I can give you some lead for current and future scientist. With that said......

    I understand that our brains function somewhat on the quantum level as observers, and in a theory on parallel Universes that I saw on the science channel, or history channel, or whatever...It said something about that in one theory an infinite number of parrallel universes exist at the same time as ours in the same spot, and that every single decision you make or even think not only plays out in alternate universes, but puts you into the universe in which that decision was made by you.

    How can we prove this? It's something that makes sense and I think that if proven should be general knowelege so everyone could reach their full potential. (little of track side note)

    Now, here is something I want to add to that. that theory was good, and im sure I didnt hear everything that the theory implies but, if no one has said it so far...I have this little question/comment to make

    If you decide to take a certain path or make a certain choice, the outcome cannot always be what you want it to be If other people are in play in your decisions because they have the same ability as you (to think and make choices) and can contradict the choice you make.... although according to the theory all choices and consequences play out in parallel universes..

    for example....

    In a parallel universe you decide to do something bad (hopefully not) and get away with it like lets say rob a bank. The reason that you get caught however, in most of the universes, even if you think in an alternate universe you will get away with it, is because the people who are around you including police and the people inside the bank think and observe completely opposite and contradictory to you and their decisions and thoughts would change your outcome instead of you having your way...


    I dont know if I am overthinking all this or not, but im about to find out with your comments. thanks for taking the time to read this...
     
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  3. Jul 7, 2009 #2

    diazona

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    Yeah, maybe you are overthinking it. A physicist's point of view is that those other parallel universes would not interact with ours, so it's meaningless to speculate about what might be happening in them or whether they even exist. The theory cannot be proven or disproven, and because of that it's not science - just philosophy.

    Of course, there could be a variant of the theory in which other parallel universes do interact with ours, and in that case it does become a scientific question, because it would then be possible (in principle) to do some sort of experiment to tell whether the parallel universe hypothesis correctly describes reality or not.
     
  4. Jul 7, 2009 #3
    Hey, thanks for the reply.

    Here is the thing...In the theory technically you do interact with the parallel universes with every choice you make in your daily life because once you make a decision, you enter the universe in which you live your decisions consequenceses, good or bad.
     
  5. Jul 7, 2009 #4

    malawi_glenn

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    "The theory cannot be proven or disproven, and because of that it's not science - just philosophy"

    I agree and you should read this carefully since this is a physics sub-forum, we have philosophy subforums as well here.
     
  6. Jul 7, 2009 #5

    Fredrik

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    I find it amusing that every time someone brings up "interpretations", someone always says that interpretations are philosophy rather than science. I agree that it isn't very scientific to make speculative statements that can't be falsified, but it seems even less appropriate to call it philosophy. The reasoning that you have to go through to realize that the details of an interpretation isn't science, that's philosophy. The interpretations themselves are not.

    Also, it's not completely unscientific to talk about interpretations. If your goal is to find one interpretation that's more suitable for generalization to a new theory, then you're definitely doing science. (Probably not very successfully, but that's another matter).
     
  7. Jul 7, 2009 #6

    malawi_glenn

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    It depends on what view one has, talking about HOW science should be done is a sub-branch of philosophy as well ;-)
     
  8. Jul 7, 2009 #7

    Demystifier

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    I completely agree! :approve:
    Especially with:
    "If your goal is to find one interpretation that's more suitable for generalization to a new theory, then you're definitely doing science."
     
  9. Jul 7, 2009 #8

    Fredrik

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    Sounds like Everett's many-worlds intepretation (MWI), except for the "in the same spot part". Forget that part. Events in the other worlds wouldn't have a position in our world.

    We can't prove it. That isn't really a problem, because no theories are ever proven. A real problem is that we wouldn't be able to disprove it if it's wrong. It's not "falsifiable". An even more serious problem in my opinion, is that there doesn't seem to be a consistent set of statements that defines the MWI. A consistent set of statements that can't be falsified isn't a theory, and the MWI isn't even a consistent set of statements, so it's even less than something that isn't a theory.

    That's my take on it, but this is not a consensus view among physicists. Some of them still take it seriously. It actually became more popular after the concept of "decoherence" was discovered (in the 80's I think), because it seems to solve one of the major problems of the MWI.

    I don't see what your question is here.
     
  10. Jul 7, 2009 #9

    Demystifier

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    I completely agree with the statements above. However, my opinion on MWI is rather positive (which may be surprising to those who know that I am a Bohmian), provided that MWI is not taken as a well defined theory, but as a framework for a research program. At least some aspects of MWI seem very appealing (for example the axiom that the wave function never collapses), and the issue is to exploit the appealing properties of MWI to construct a closed self-consistent theory compatible with observations. In fact, Bohmian mechanics is also a variant of MWI theory, because it also says that the wave function never collapses and proposes an explanation of the fact that, after decoherence, only one branch of the wave function is perceived.

    For me, the worst part of MWI is its name: many WORLD interpretation. I believe that this interpretation would be much more appealing to most physicists if it was called many BRANCH interpretation (MBI) instead. There is only one world (the configuration space on which the wave function is defined), but the wave function has many branches on this space that, due to decoherence, do not overlap.
     
  11. Jul 7, 2009 #10
    I disagree with this. MWI can be falsified because one can in principle falsify that isolated systems evolve according to unitary time evolution. The existence of parallel universes only depends on the assumption that time evolution is unitary.

    This parallel universes controversy is similar to the queston whether or not the universe stops to exist exactly at the horizon 13.7 billion light years away.
     
  12. Jul 7, 2009 #11
    So you are saying that there one universes time evolution is Not at the same time evolution as another and because of that it can be falsified?
     
  13. Jul 7, 2009 #12
    your a bad science advisor...im asking to learn more and understand your just shooting down this thread and my other thread because in your mind im in no position to talk about this or something...grow up.
     
  14. Jul 7, 2009 #13
    We can't prove it. That isn't really a problem, because no theories are ever proven. A real problem is that we wouldn't be able to disprove it if it's wrong. It's not "falsifiable". An even more serious problem in my opinion, is that there doesn't seem to be a consistent set of statements that defines the MWI. A consistent set of statements that can't be falsified isn't a theory, and the MWI isn't even a consistent set of statements, so it's even less than something that isn't a theory.

    That's my take on it, but this is not a consensus view among physicists. Some of them still take it seriously. It actually became more popular after the concept of "decoherence" was discovered (in the 80's I think), because it seems to solve one of the major problems of the MWI.[/QUOTE]

    ok, so what do you believe is missing for there to be a consistent set of statements?
    anyone have any ideas?
     
  15. Jul 7, 2009 #14
    No, what I mean is what Tegmark explains in this article:

    http://arxiv.org/abs/0905.2182

    So, what is assumed is that the wavefunction of the universe evolves according to the Schrödinger equation, nothing more. This alone implies the "many worlds" and this assumption is also falsifiable.
     
  16. Jul 7, 2009 #15

    Fredrik

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    A derivation of the probability rule of quantum mechanics from the axiom that every isolated system changes with time as described by the Schrödinger equation. It's very likely that this can't be done.
     
  17. Jul 7, 2009 #16

    Why not add the Born rule as an additional postulate then? It suffices to add the postulate that observing an observable if the state of the system is in an eigenstate of that observable, will yield the corresponding eigenvalue with certainty.
     
  18. Jul 8, 2009 #17



    english plz...for the lost like me...lol
     
  19. Jul 9, 2009 #18

    Fredrik

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    I think it's absolutely necessary to do that, or rather to not remove it from the standard formulation of QM in the first place. My point is, Tegmark says that Everett's MWI is defined by the single axiom of unitary time evolution. If we allow other axioms, are we still talking about the MWI? I think MWI proponents need to be much more clear about what exactly their interpretation is saying.

    While writing this reply, I realized something that I hadn't before. I've been thinking of Born's probability rule and von Neumann's projection postulate as two parts of the same axiom, but they are of course independent. We need to keep the Born rule in the theory, but we can probably drop the projection postulate. With the Born rule intact, we may* have all we need to do decoherence calculations, which lead to an approximate version of the projection postulate.

    *) I don't know if the Born rule implies that the Hilbert space of a composite system is the tensor product of the Hilbert spaces of the subsystems, so we may need an additional axiom.

    I would say that this is a non-crazy version of the MWI: "We should drop the projection postulate from the standard formulation of QM because it contradicts the time evolution axiom, and because decoherence gives us an approximate version of it anyway". The problem is, it also sounds like a non-crazy version of the Copenhagen interpretation. I have never really thought that Bohr and Heisenberg actually believed that the collapse is exact. They were too smart for that.

    So what exactly is the difference between non-crazy MWI and non-crazy CI? I would say that the statement that defines the MWI isn't unitary time evolution, but the claim that QM actually describes the universe, as opposed to just being a set of rules that tell us how to compute probabilities of possible results of experiments given the results of other experiments.

    If the idea is to derive the Born rule, I think you also need to postulate that the Hilbert space of the universe is the tensor product of the Hilbert spaces of its subsystems.
     
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