Conservation of energy in quantum physics

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Discussion Overview

The discussion revolves around the conservation of energy in quantum physics, specifically focusing on the behavior of an electron in a hydrogen atom during observation and the implications of its position, potential energy, angular momentum, and mass. The scope includes conceptual exploration and thought experiments related to quantum mechanics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that an electron's position is probabilistic until observed, and proposes a thought experiment regarding its potential energy and angular momentum changes upon observation.
  • Another participant argues that potential energy and angular momentum also have uncertainties, challenging the assertion that they should change in a definitive manner.
  • A further comment states that in non-relativistic quantum mechanics, the mass of particles is constant, indicating that it cannot change as suggested.
  • Participants discuss the distinction between thought experiments and established theories, with one noting that quantum physics has well-developed theories in quantum mechanics and quantum field theory.
  • There is a recognition of the need for precise language, with one participant acknowledging the use of "theory" when they meant "hypothesis."

Areas of Agreement / Disagreement

Participants express differing views on the implications of observation in quantum mechanics, particularly regarding potential energy, angular momentum, and mass. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Limitations include the uncertainty associated with quantum quantities and the implications of observation, as well as the distinction between thought experiments and established theories. There are unresolved aspects regarding the interpretation of energy conservation in this context.

Who May Find This Useful

Individuals interested in quantum mechanics, thought experiments in physics, and the conceptual challenges of energy conservation in quantum systems may find this discussion relevant.

IAmJustCurious
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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.
 
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IAmJustCurious said:
it should gain potential enegry fivefold.
Beside position, the potential energy also has some uncertainty. Thus, saying "it should" will go against the theory.

IAmJustCurious said:
it's angular momentum should increase
Yet another quantity having nonzero uncertainty is the angular momentum.

IAmJustCurious said:
as well as the mass of the entire atom due to E=mc²"
In non-relativistic QM, mass of particles are constant, i.e. it cannot have any other value than what it is already given.
 
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blue_leaf77 said:
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.
Thanks for pointing out the holes in my theory.
 
IAmJustCurious said:
Thanks for pointing out the holes in my theory.
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.
 
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blue_leaf77 said:
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.
Sorry I should have said something like hypothesis. You're right
 
Hello curious :welcome:

Keep up the curiosity !
 
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