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B Conservation of energy in quantum physics

  1. Aug 5, 2016 #1
    I am still in secondary school so I probably shouldn't think about things this complicated (at least that's what it seems to me, complicated), but please correct me if I'm wrong. If I recall correctly, the position of an electron is never certain, and always based on probability, unless observed. Now let's do a though experiment in an isolated system:

    "The electron of a simple Hydrogen atom is located at 0.1 nm from its single proton when observed, but due to my understanding of how physics works. When - after this observation the electron stays unobserved for a tiny moment of time, and - after that it's been observed at 0.5 nm, it should gain potential enegry fivefold. Also, it's angular momentum should increase, as well as the mass of the entire atom due to E=mc²"

    I know I'm probably wrong, and it has something to do with the velocity of the electron changing or something like that, but I was wondering what the actual answer would be, and it's fun to think about.
  2. jcsd
  3. Aug 5, 2016 #2


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    Beside position, the potential energy also has some uncertainty. Thus, saying "it should" will go against the theory.

    Yet another quantity having nonzero uncertainty is the angular momentum.

    In non-relativistic QM, mass of particles are constant, i.e. it cannot have any other value than what it is already given.
  4. Aug 5, 2016 #3
    Thanks for pointing out the holes in my theory.
  5. Aug 5, 2016 #4


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    Just want to let you know, thought experiment is different from a theory. Speaking of the theory of quantum physics, it has been well developed in quantum mechanics and quantum field theory, and these are already mature theories by now.
  6. Aug 5, 2016 #5
    Sorry I should have said something like hypothesis. You're right
  7. Aug 5, 2016 #6


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    Hello curious :welcome:

    Keep up the curiosity !
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