What constitutes a QM observation?

  1. When discussing quantum mechanics, what constitutes an observation?

    -Glenn
     
  2. jcsd
  3. jcsd

    jcsd 2,226
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    Re: observation?

    'Measurment' is the temr usually used, unfortunately there is no precise defintion for what constitutes a measurement apparatus and thus a measurment(this is known as the quantum mechanical measurement). The best definiton is probably: "an irrevesrible change to the measurmewnt apparatus".
     
  4. I guess I am still not clear on the "observation" part of all this. In a book I am reading, the author is repeatedly referring to them as "conscious" observations, or "intelligent" observations.

    Is there a clearer explanation?

    Thanks,
    Glenn
     
  5. jcsd

    jcsd 2,226
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    An observer is the person who makes the measurment. It's a sticky subject as there are many theories on how to resolve the quantum mechanical measurment problem, but no defintive answer.
     
  6. chroot

    chroot 10,426
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    Generally, you consider closed systems. Anything inside that closed system that is made to affect something outside the system (therefore making it no longer "closed") is a measurement.

    - Warren
     
  7. Can a subatomic particle, atom, molecule, or larger cause the collapse of its own wave function?

    -Glenn
     
  8. selfAdjoint

    selfAdjoint 8,147
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    No, but its interaction with things around it can. Look up decoherence.
     
  9. jby

    jby 0

    I don't quite understand this. How does something inside a closed system affect something outside the system? After all, this seems contradictory to the word closed. Seems like a tongue twister to me. :P
     
  10. jcsd

    jcsd 2,226
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    In convential quantum mechanics no, but there is a theory of spontaneous collapse where in a manner simlair to radioactive decay wavefunctions of particles spopntaously collapse, howvere attempts to detect any spontaneous collapse have failed.
     
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