Questions on Many Worlds Interpretation

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Discussion Overview

The discussion revolves around the Many Worlds Interpretation (MWI) of quantum physics, focusing on the nature of parallel universes, their visibility, and the composition of these universes. Participants explore theoretical implications, conceptual clarifications, and personal interpretations related to MWI.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Rusty questions why parallel universes in MWI are not observable if they exist in the same space as our universe, suggesting there must be something different about the particles or atoms in these universes.
  • Rusty also inquires about the nature of the parallel universes and what they are made of when they split off from each other.
  • One participant suggests that decoherence explains the lack of visibility of other universes by correlating the system with macroscopically distinguishable states of memory.
  • Another participant posits that all worlds are part of a single physical system, implying they are made of the same fundamental stuff.
  • There is a discussion about the distinction between pure and mixed quantum states, with one participant explaining that mixed states can be represented as combinations of pure states.
  • Rusty expresses confusion about the concept of subsystems and the state of the universe, seeking clarification on how these relate to the MWI.
  • One participant introduces the principle of linearity of quantum mechanics as a potential answer to what separates different worlds.
  • Another participant offers a metaphor involving a sewing needle and paper to illustrate how atoms might interact in a multi-dimensional context.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and interpretation of MWI, with no consensus reached on the nature of parallel universes or the answers to Rusty's questions. Multiple competing views and uncertainties remain throughout the discussion.

Contextual Notes

Participants acknowledge limitations in their understanding of MWI, with some expressing the need for clearer definitions and explanations of terms like "pure" and "mixed" states. The discussion reflects a range of interpretations and conceptual challenges without resolving these complexities.

  • #31
Demystifier said:
It was just an impression, I cannot give a good rational argument for that.

Ah, yes, I was totally convinced that BM was true, but it happened in another MWI branch :)
 
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  • #32
Dmitry67 said:
Ah, yes, I was totally convinced that BM was true, but it happened in another MWI branch :)
Is that a joke? I think it isn't if you honestly believe in MWI. :)
 
  • #33
So both of them being equaly valid states, they can exist? then, to me it is clear that quantum theory, no mater how precise, is far from being understood (at least, it's relation with reality).
 
  • #34
The theory is well understood. The reasons why it works aren't. Note that this is always the case with the best theory we know, because if we had a theory that explains why it works, that would be a better theory.
 
  • #35
Yes, they both exist.
'you' are not a line... Some of 'you' are living quite different lives in the other worlds, even they share the same history to some moment of time.

Here is a very good FAQ:
http://plato.stanford.edu/entries/qm-manyworlds/

covering even questions like:
6.4 Social Behavior of a Believer in the MWI
:)
 
  • #36
LOL. Sorry, I'm as clear as a closed book. I don't mean the theory is not well understood, but it's just maths applied to something. What I am not sure is what "something" applies for. As for there being a "me" conscious of having chosen another option, I don't have it. What the theory says is a may be smeared out between both states, not that any of them has an independent existence
 
  • #37
Re: that immortal cat in the unopened box... before the box is opened, what if a person is looking at pictures in the same room... should that change anything? I wouldn't think so. What if there is a mechanical device that is running inside the box... this, in and of itself, should not change anything. But what if that mechanical device is a web camera taking pictures and posting them somewhere on the web? What the mechanical device 'is' and 'does', should not change anything. Finally what if the pictures that are being looked at are the ones from the camera!?

At what point does the probability wave collapse?

Regardless of the answer, if the pic shows the cat is alive, a new wave has formed since the pic was taken... however, if the cat is dead then the game is over. This means something but... LOL!... I'm not sure what just yet. Maybe this test should use the random event to flip a coin instead so that there is more of a balance... or maybe I'm just over medicated once again. ;-)

Rusty

Edit: It seems to me -- this shows that the cat is either dead or alive regardless of observation and that the cat is never both alive and dead -- this is all within your head.
 
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