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How does Many Worlds theory explain Schroedinger's cat

  1. Mar 29, 2009 #1
    As I understand it, when Schroedinger's "box" is opened, then a dead cat comes into existence in one universe and a live cat in another. However, in a variation to this experiment, in which there is say a 10% chance of the cat living and 90% dying, when the box is opened does one live cat come into being in one universe and 9 dead cats appear in 9 identical universes.

    If this is the case then as the 9 universes with the dead cats are identical would they merge into one, which overall has the end effect of making the live/dead odds of 50%
  2. jcsd
  3. Mar 29, 2009 #2
    The way I understand it, the many worlds theory doesn't say that the dead/living cat "comes into existence" at all, but rather that the universe splits at every instant in which the cat might die. It just so happens that every second, there's a (let's say) 50/50 chance of the cat dying. The cat you observe depends on which cat exists in your universe. So (for the sake of argument) for t=1, there's 2 universes, one where the cat's living, one where it's dead. at t=2, there's 3 universes. one where the cat's living, one where it JUST died, and one where it died two seconds ago. From my understanding, it removes the whole idea of "observation" from quantum mechanics... but I'm in absolutely no way an authority on these matters and have possibly gotten more things wrong than right. This is just how I understand it.
    edit: also, from my understanding, these universes live in the same space but have decohered from one another, so that they're on another frequency, so to speak.
  4. Mar 30, 2009 #3
    Off topic, but do they go over this stuff in college?
  5. Apr 3, 2009 #4
    I know they go over the uncertainty principle and such but I don't know if they address the many worlds interpretation of quantum mechanics. I'm a second year CSC major at CalPoly (SLO) and know a few physics majors who have taken a course called "Modern Physics", which is basically quantum mechanics but I've no clue how deep they delve into the subject matter. I wish that class was part of my degree, though.
  6. Apr 6, 2009 #5


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    We didn't go over interpretations at all in my undergrad study. They're not really necessary for most work you'll do in the field. It's either a philosophical question, or a highly theoretical one.
  7. Apr 7, 2009 #6
    I love how easily the line between philosophy and physics is blurred. Seems something worth doing (I don't know if I'll ever forgive Carlin for mocking our space program. haha).
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