How is the Born rule deduced from decoherence?

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    Born rule Decoherence
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Discussion Overview

The discussion revolves around the relationship between decoherence and the Born rule, particularly in the context of the measurement problem in quantum mechanics. Participants explore interpretations of Weinberg's statements regarding these concepts and seek further references to clarify their understanding.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants reference Weinberg's "Lectures on Quantum Mechanics," suggesting that he claims the Born rule can be deduced from decoherence, which they believe addresses the measurement problem.
  • Others argue that decoherence does not solve the measurement problem, indicating a distinction between the measurement problem and the Born rule.
  • There is a request for clarification on the exact wording of Weinberg's claims, with one participant expressing skepticism about the interpretation of his statements.
  • Some participants highlight that decoherence only appears to solve the measurement problem and does not provide a definitive solution.
  • References to additional literature on decoherence and its implications in quantum mechanics are provided, including works by M. Schlosshauer.
  • One participant emphasizes the importance of understanding the phases in superpositions and how they interact with the environment, as discussed in a linked lecture.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether decoherence solves the measurement problem or adequately explains the Born rule. Multiple competing views remain, with some asserting that decoherence does not resolve these issues while others reference Weinberg's work as supportive of their position.

Contextual Notes

There are limitations in the discussion regarding the interpretation of Weinberg's statements, as well as the definitions of the measurement problem and the Born rule. Some participants express uncertainty about the implications of decoherence and its relationship to the Born rule.

Jamister
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TL;DR
measurement problem (i.e born rule) is solved by decoherence
Weinberg says in his book "Lectures on Quantum Mechanics" that the born rule can be deduced from decoherence, and this solves the measurement problem. I'm looking for reference, book or article, to understand this better.
Thank you
 
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Maybe he means in the MWI.
 
EPR said:
Maybe he means in the MWI.
What is MWI?
 
orisomech said:
Summary:: measurement problem (i.e born rule) is solved by decoherence

Weinberg says in his book "Lectures on Quantum Mechanics" that the born rule can be deduced from decoherence, and this solves the measurement problem.
Decoherence does not solve the measurement problem.
 
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Jamister said:
Weinberg says in his book "Lectures on Quantum Mechanics" that the born rule can be deduced from decoherence, and this solves the measurement problem.
Can you quote his exact statement? Because I don't think that that's exactly what he says.
 
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Demystifier said:
Can you quote his exact statement? Because I don't think that that's exactly what he says.
Well, it's hard to quote one sentence, because it is on entirely 3 pages.
one of the quotes is this (on page 92):
1601288538002.png

and another one is this (on page 91):
1601288039347.png

but I also attach the book itself where this claim is on pages 90-92.

[Mentor Note -- Copyrighted PDF copy of the book has been removed]
 
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The measurement problem is different from the Born rule, but anyway:

For any given experiment, the possible measurement results must decohere if they are to be resolved by an experiment. If they do not decohere, they cannot be resolved by an experiment.
 
Jamister said:
Well, it's hard to quote one sentence, because it is on entirely 3 pages.
one of the quotes is this (on page 92):
View attachment 270117
and another one is this (on page 91):
View attachment 270116
but I also attach the book itself where this claim is on pages 90-92.
Well, he says
So where does the Born rule come from? There are two main approaches to this question, that are often called instrumentalist and realist, each with its own drawbacks.
you said that he claims that the Born rule can be deduced from decoherence. I think you need to read more carefully.
 
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Jamister said:
Well, it's hard to quote one sentence, because it is on entirely 3 pages.
one of the quotes is this (on page 92):
View attachment 270117
and another one is this (on page 91):
He says that there is a widespread impression that decoherence solves the problem, then he goes on to point out why it only seems so, but in fact is not a solution.
 
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  • #11
Jamister said:
Well, it's hard to quote one sentence, because it is on entirely 3 pages.
one of the quotes is this (on page 92):
View attachment 270117
and another one is this (on page 91):
View attachment 270116
but I also attach the book itself where this claim is on pages 90-92.
In those quotes he never says that it explains the Born rule. And concerning the claim that decoherence solves all problems, he uses phrases "there seems to be a wide-spread impression" and "has to do with". So it's far from a definite statement that decoherence solves the problems.

And by the way, it's illegal to attach the whole book. Next time attach only a few relevant pages.

For more on decoherence, you might want to see my lecture
http://thphys.irb.hr/wiki/main/images/5/50/QFound3.pdf
 
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  • #12
Thank you for the replies. I respond to - Demystifier , martinbn,
A. Neumaier. I didn't mean that decoherence solves the problem of born rule completely, but I didn't understand his point in the book and I want to read more about it. Do you know a good source for it?
 
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Jamister said:
I didn't mean that decoherence solves the problem of born rule completely, but I didn't understand his point in the book and I want to read more about it. Do you know a good source for it?
  • M. Schlosshauer, Decoherence, the measurement problem, and interpretations of quantum mechanics, Rev. Mod. Phys. 76 (2005), 1267–305.
  • M. Schlosshauer, Decoherence and the quantum-to-classical transition, Springer, New York 2007.
 
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  • #15
Jamister said:
from your presentation
Why do you say that :
View attachment 270125
how did you get there?
If you understood everything before that claim, then you should understand that claim as well. To have a coherent superposition one should know the phases in front of the two terms, but as explained in the lecture the phases are "eaten up" by the environment.
 

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