I Conservation of energy and wave function collapse

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The discussion centers on the claim that the collapse of the wave function in quantum mechanics (QM) can violate conservation of energy, as suggested by a referenced paper. It is noted that while unitary dynamics in QM respects conservation laws, the collapse process lacks a well-defined dynamics, leading to potential violations. The conversation also highlights that collapse is not universally accepted as a physical process and is often treated as a mathematical update upon measurement. Participants argue that any perceived violation of energy conservation must consider the entire system, including the measuring device, rather than isolating the quantum system. Ultimately, the interpretation of wave function collapse remains a contentious topic, with no consensus on its implications for conservation laws.
  • #31
pines-demon said:
You put some energy to prepare the state, then you measure some energy (plus the energy you gain-lose in order to perform the measurement).
Doing this requires considering the system you are measuring as an open system--it exchanges energy with other systems, during measurement, and also, as you point out, during preparation. So you would not expect the energy of the system alone to be conserved at all; it's an open system. To evaluate conservation of energy at all, you would need to include other systems as well. (And you still have the issue @Nugatory raised in post #31 to deal with.)

But the point is that the paper referenced in the OP does not do any of that. It only looks at the system being measured (and as far as I can tell, it does not look at the preparation process at all). So any evaluation it makes of conservation of energy can't possibly be correct.
 
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  • #32
Lord Jestocost said:
If one accepts that the quantum mechanical state function ##\Psi## is nothing more than a catalog of knowledge following from one observed fact and determining the probabilities for possible future events, issues such as “energy is not conserved in quantum mechanics” become obsolete.
If you take this approach, the question becomes interpretation dependent. And discussion of that aspect belongs in the interpretations subforum.

However, other points being made in this thread are not dependent on any interpretation.
 
  • #33
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  • #34
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