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9 lives of Shroedinger's Cat

  1. Sep 21, 2004 #1
    In the famous thought experiment of Shroedinger’s Cat, we never consider the cat itself as an observer. The cat would no doubt be able to tell whether it is dead or alive without anyone opening the box. I think this is just a problem of semantics and if you were to replace the cat with a binary random number generator the paradox would still be there.
  2. jcsd
  3. Sep 21, 2004 #2
    The cat is supposed to be in a quantum supperposed state. Of course it is not happening with macroscopic objects. Macroscopic objects cannot be in a supeposed state because of decoherence due to large statistics. Is that what you mean when you say the cat is an observer, because it would destroy coherence ? Erwin's point was exactly that, if you talk to people about atoms, they do not listen. If you talk to them about the cute little kitty, and say you are going to torture it, then they listen. :smile:
  4. Sep 21, 2004 #3
    The cat itself is an observer. The cat is either dead or alive. The rules of QM don't apply here. Only the outside observer's lack of knowledge is involved . His knowledge is in an OR state. The QM state is an AND state.

  5. Sep 21, 2004 #4
    This is not very accurate a statement : the observer's knoledge is a XOR about the cat and a AND about the atom, whence the paradox. As you said, the cat is an observer, or causes decoherence, and so the knowledge for the atom is a XOR too, and in the end there is no paradox.
  6. Sep 21, 2004 #5
    That's right. but the XOR condition excludes an AND condition,
    so there can be no superposition.

  7. Sep 21, 2004 #6
    The Grad student

    A grad student pointed that out to me, that the cat is also an observer. I know what you mean by the macroscopic cat not being in a quantum supperposed state. I was more or less having fun with Shroedinger's Cat and I also wante to point out that the object being observed does not have to be what we might call an animate object. If there is such a thing as an inanimate obeject?
  8. Sep 21, 2004 #7
    It must only be any macroscopic object, so that decoherence applies.
  9. Sep 22, 2004 #8
    wave collapse

    Well I always thought that the act of observation is supposed to collapse the wave function. I have also wondered if the collapse may due to the introduction of measurement and not a real property of the universe.I will admut though that I am more a philosopher than a physicist so any information would be helpful. Thanks
  10. Sep 22, 2004 #9
    The collapse is said to be due to measurement. However, any interaction with a macroscopic object, be it measurement or not, will cause the collapse. It "could have been" a measurement, and can be called a "measurement" in a generalized meaning.
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