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I Question about observation

  1. Mar 22, 2017 #1
    The QM is saying that a particle in some potential pattern will have a wavefunction that describes the probability to find the particle. And then it also said that observation will make wavefunction collapse into measured value. For example, the electron in an atom will be in one position after measuring its position.

    But I have a strange idea about this thing. The situation is that now there is a particle with energy E. There is a potential barrier in front of it which has potential V that is V>0. Also, 0<E<V. This means there can be quantum tunneling. Now if the particle can observe itself, what will it see when it performs quantum tunneling?
  2. jcsd
  3. Mar 22, 2017 #2


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    A particle observing itself is a meaningless concept. Any "observation" would have to be by an outside agent.
  4. Mar 22, 2017 #3
    maybe I didn't ask it clearly. Actually I am thinking that the particle defined its own position and made its own wavefunction collapse. So it would not have anymore chance to quantum tunnel? But it should tunnel because for outside observer, the wavefunction includes quantum tunneling.
  5. Mar 22, 2017 #4


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    I have no idea what that means.
  6. Mar 22, 2017 #5
    Sentient subatomic particles with free will?
  7. Mar 22, 2017 #6


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    This is one of the most common misunderstandings of quantum mechanics. "Observation", in the ordinary English-language meaning of the word, has nothing to do with whether the wave function collapses; just about any interaction with something large enough to be considered a classical object will collapse the wave function. (The confusion with observation comes about because the lab equipment that we'd use to observe the position has to be a reasonably large classical object).
    But it can't. We need an interaction with a sufficiently large classical object to collapse the wave function, and we don't have that here.
  8. Mar 22, 2017 #7
    An interaction between a microscopic object and another microscopic object simply entangles them. I don't think a microscopic object can observe itself, as it may mess with QM predictions.
  9. Mar 23, 2017 #8
    I see, so the condition in my question actually cannot happen. Thank you for the replies.
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