Problem with Schrodinger's Cat

Discussion in 'Physics & Math' started by Journey0820, Jul 7, 2007.

  1. Pete It's not rocket surgery Moderator

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    Many-worlds interpretation, first published in the physics literature in 1957 as the doctoral thesis of Hugh Everett.
     
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  3. Journey0820 Registered Member

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    And it is just as stupid an idea half a century later.
     
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  5. Pete It's not rocket surgery Moderator

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    Yes. But just how stupid is that? Opinion is divided.
     
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  7. Aivar A.R. Registered Senior Member

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    Hm, I haven't read the whole topic, but here's a question...

    What if I don't measure a value of an object, but look at it? Would that qualify as defining moment?

    I mean, if I look at something and think it's big. Or stretchy. But I only take a vague look and don't measure it, so I don't really know.
     
  8. Kojax Registered Member

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    I get a kick out of philosophical questions like these. They try to treat practical reality the same as theorhetical reality, which is always confusing, but never terribly accurate.

    We experience the cat as being both potentially dead and potentially alive until we open the box. Then, with the new information, our experience changes.

    I get the impression that this is true of subatomic particles as well. Knowing their position doesn't tell us their velocity. Knowing their velocity doesn't tell us their position. We can never experience knowing both at once.
     
  9. Lasse Ronnenberg Registered Member

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    Schrödinger's Cat has a certain probability of being alive and dead before you open the box. But while the box remains closed, a scientist might say "It is both alive and dead right now" to indicate that both are possible and that you won't know for sure until after you have opened the box, at which time the cat's probability function 'collapses' into either 100% alive or 100% dead.

    That said, let me propose a comparison without a cat in a box: Use Schrödinger's principle to determine where in a storm cloud a lightning strike resides.
    At first you have a probability distribution showing you that the lightning strike most likely exists in the center of the cloud, and is less likely to be found near its outer edges.
    Scientists that say "The cat is both alive and dead" would say "The lightning strike is EVERYWHERE in the cloud right now".
    Then, after the lightning strikes a tree, they will tell you "The lightning strike was right there with 100% certainty (as opposed to being 'everywhere at once').

    The thing is: Electrons and lightning-strikes have something in common, that they do not share with cats.
    Cats are either alive or dead - we just don't know which, until we measure it or open the box.
    But a lightning strike really does exist 'everywhere' within the cloud, right up until it strikes.

    Now, this should lead you to ask: What else does quantum particles and lightning strikes have in common? Could an electron actually have something in common with a charged cloud? Could a lightning-stike be compared to measuring the position of an electron? And if an electron was made of even smaller charges (like how lightning is made of super fast tiny electrons) then does the collapse of the probability function actually occur faster than the speed of light (just like how the electrons at the far edge of the raincloud suddenly materialize into a single lightning strike at speeds much faster than that of the lightning strike itself? And finally: If sub-electron charges could move from every location in an electron cloud and into a single point for the measurement of its location, then, when they move faster than the speed of light, do they actually materialize backwards in time? Or does all velocities faster than light, when observed by a human, look like they merely happen instantaneous - the moment we measure them. (And could any of this explain why electrons seem to 'skip' around a nucleus, rather than moving with a continuous motion?) - every answer leads to more question, but I think lightning clouds may have more in common with quantum particles than just their probability functions

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  10. Kristoffer Giant Hyrax Valued Senior Member

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    Thread's been dead for ten years Lasse.
     
  11. Lasse Ronnenberg Registered Member

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    Unfortunately it also shows up at the very top when you google for "Schrödinger's Cat Debunked"

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  12. Dinosaur Rational Skeptic Valued Senior Member

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    From Pete Post 61 & Journey0820 Post 62
    I do not think that Everett’s 1957 paper is as silly as the interpretations of it by others are.

    The above is an opinion I had many decades ago when I had read Everett's paper.

    It is interesting to note that the popular version of many worlds is easier to understand than any of the other interpretations, which is the reason for its popularity among both some experts & many lay folks.

    Those who accept the popular version would reject it if they considered the implications.

    A new universe for every possible outcome of a quantum level phenomenon, with each new universe spawning more universes.​

    I do not think Everett’s paper made the above claim, but perhaps my not infallible memory is incorrect.
     
  13. Dinosaur Rational Skeptic Valued Senior Member

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    The Schrödinger's Cat controversy is a bit silly.

    The Schrodinger thought experiment involved a cat in a closed container accompanied by a quantum level process, one outcome of which would result in the cat's death. The claim is that since the outcome of the quantum level process is in some limbo state, the cat is also in some limbo state, neither dead nor alive.

    The issue relates to a Bohr POV that a quantum level entity does not have certain properties until there is an interaction at the classical level.

    This POV has been erroneously interpreted as a claim that the properties do not manifest until a conscious observer sees/measures the results of an experiment.​

    The cat is not a quantum level entity & I am sure that Bohr would agree that it could not actually be in a limbo state prior to some such interaction. Its state would merely be unknown until observed.
     
  14. Contemplation Registered Member

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    I think the main reason why physicist believe in the Many Worlds Interpretation of quantum mechanics is because of Schrodinger's Cat. It avoids the problem of a cat being in two states at once until observed. Cats cannot be in a state of superposition, so I couldn't see any reason why that would hold any relevance myself. Although, the inventor of quantum computing claims that he was able to work with materials that could be in a state of superposition. Then I find that hard to believe.
     
  15. birch Valued Senior Member

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    On the quantum level, schrodinger's cat is like trying to pin down or guess at what point an object/particle is located that is traveling back and forth from point a to b to c etc and back again at very high velocity. You dont know if its at a, b or c until you open the box to observe it at that precise time. This is the state.

    With a cat, its easier as its alive or dead if thats the only parameter being measured.
     

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