Difference Between Two Thoughts on Wave Function Collapse?

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Discussion Overview

The discussion centers around differing interpretations of wave function collapse in quantum physics, particularly the distinction between the observer's role in the collapse process. Participants explore the implications of these interpretations and their philosophical underpinnings, as well as the relevance of a specific book on quantum physics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the wave function collapse occurs when any observer looks at the system, suggesting a real and objective collapse.
  • Others argue that the wave function may not be real but rather represents an observer's knowledge, leading to the idea that collapse happens when an individual observes the system.
  • A later reply questions the implications of the observer being subject to the same physical laws as the quantum system, suggesting that this leads to paradoxes such as the cat being both dead and alive.
  • Participants mention alternative interpretations, including Many Worlds and Bohmian Mechanics, as ways to address the issues raised by the observer's role in wave function collapse.
  • Some participants critique the book "The Dancing Wu Li Masters," describing it as a mix of physics and mysticism, and suggest it lacks academic rigor.
  • Recommendations for better resources include Feynman's "QED" and Susskind's "Quantum Mechanics Theoretical Minimum," which are noted for their clarity and mathematical rigor.

Areas of Agreement / Disagreement

Participants express multiple competing views on the nature of wave function collapse, with no consensus reached on which interpretation is correct or preferable. There is also disagreement regarding the value of the book mentioned, with some finding it lacking in academic quality.

Contextual Notes

Participants acknowledge the limitations of the discussed book in providing a solid foundation in quantum physics, highlighting its lack of mathematical explanations and concrete details. The discussion also reflects the complexity and ongoing debates surrounding interpretations of quantum mechanics.

Who May Find This Useful

This discussion may be useful for individuals interested in quantum physics, particularly those exploring philosophical interpretations of wave function collapse and seeking recommendations for educational resources in the field.

cmkluza
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I've recently been reading the book The Dancing Wu Li Masters which is supposed to be a very basic introduction to quantum physics. I have a question on the following quote:

"Up to now, we have said that the collapse occurs when somebody looks at the observed system. This is only one point of view. Another opinion [...] is that the wave function collapses when I look at the observed system."

I'm new to quantum physics in general, so I was wondering what the difference was between "somebody" and "I" looking at the observed system in. I'm questioning it since it was so specifically expressed as two opinions on the question of when the wave function collapses.

Thanks for any help/enlightenment anyone can offer!
 
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There are two views on wave function collapse. One is that the wave function is real and really collapses. In this case, presumably the collapse occurs no matter who looks at it. I had never heard this view until recently, so I think it is largely a strawman.

A second view is that the wave function is not necessarily real, and represents one's state of knowledge. In this case the wave function collapse is an update of one's knowledge, so the wave function collapses when you observe it. Of course, you are free to define who you are, and you can use another person or an instrument as a proxy for your state of knowledge. So the important distinction is that in the second case, the cut between you and the quantum system can be shifted. As far as I understand, this is the orthodox view.
 
atyy said:
So the important distinction is that in the second case, the cut between you and the quantum system can be shifted. As far as I understand, this is the orthodox view.

Thanks! I hadn't heard of the second view that you've just pointed out until now, but it seems like a very interesting way to consider the wave function.
 
cmkluza said:
Thanks! I hadn't heard of the second view that you've just pointed out until now, but it seems like a very interesting way to consider the wave function.

One reason for the second view is that if we take the wave function of the quantum system as real, and we believe the observer who collapses the wave function should obey the same underlying laws of physics as the quantum system, then we will try to write a wave function that includes quantum system and the observer. However, in that case, one finds that there is no definite result (the cat is dead and alive), contrary to our experience (the cat is dead or alive). To fix this one can try to say that there is no definite result and that all outcomes occur (Many Worlds), or we can introduce new variables (Bohmian Mechanics), or we can say that a notional cut between the observer and the quantum system is always needed, and the wave function is not necessarily real, as the cut can be subjectively shifted (orthodox Copenhagen).
 
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cmkluza said:
I've recently been reading the book The Dancing Wu Li Masters which is supposed to be a very basic introduction to quantum physics.

It's not. It's a mishmash of a caricature of physics with eastern mysticism. Read it, enjoy it, but don't think it's a good explanation of physics.
 
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Vanadium 50 said:
It's not. It's a mishmash of a caricature of physics with eastern mysticism. Read it, enjoy it, but don't think it's a good explanation of physics.
You're right about that, perhaps I should've thought more before saying what the book was about. It's certainly not anywhere near an academic level of quantum physics explanation, and I do hate the lack of mathematical/concrete explanations that it has. However, I do enjoy some of the views it has on physics in general. Just out of curiosity, what do you mean when you say it's not a good explanation of physics? Do you mean the entire book, and its thoughts? Also, (sorry to bug you more) but it sounds like you might be able to recommend some other books that I could use to learn more about physics in general, and more specifically quantum physics. Could you?

Thanks for your input!
 
cmkluza said:
You're right about that, perhaps I should've thought more before saying what the book was about. It's certainly not anywhere near an academic level of quantum physics explanation, and I do hate the lack of mathematical/concrete explanations that it has. However, I do enjoy some of the views it has on physics in general. Just out of curiosity, what do you mean when you say it's not a good explanation of physics? Do you mean the entire book, and its thoughts? Also, (sorry to bug you more) but it sounds like you might be able to recommend some other books that I could use to learn more about physics in general, and more specifically quantum physics. Could you?

I don't like that book either - it's sort of a cross between new age ideas and sensationalist views of modern physics.

A much better book is Feynmans - QED:
http://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter

And the associated video lectures:
http://www.vega.org.uk/video/subseries/8

But if you want the real deal, including the dreaded math, this is the book to get:
https://www.amazon.com/dp/0465036678/?tag=pfamazon01-20

It too has video lectures:
http://theoreticalminimum.com/

Regarding your original question decoherene has shed a lot of light on the issue:
http://www.ipod.org.uk/reality/reality_decoherence.asp

Thanks
Bill
 
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bhobba said:
I don't like that book either - it's sort of a cross between new age ideas and sensationalist views of modern physics.

A much better book is Feynmans - QED:
http://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter

And the associated video lectures:
http://www.vega.org.uk/video/subseries/8

But if you want the real deal, including the dreaded math, this is the book to get:
https://www.amazon.com/dp/0465036678/?tag=pfamazon01-20

It too has video lectures:
http://theoreticalminimum.com/

Regarding your original question decoherene has shed a lot of light on the issue:
http://www.ipod.org.uk/reality/reality_decoherence.asp

Thanks
Bill

Thanks a lot! The Theoretical Minimum looks very interesting, I'm going to have to order a copy of the book soon, and the online lectures are an awesome bonus. Thanks for your input, Bill!
 
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cmkluza said:
Thanks a lot! The Theoretical Minimum looks very interesting, I'm going to have to order a copy of the book soon, and the online lectures are an awesome bonus. Thanks for your input, Bill!

I've read a lot of Susskind's Quantum Mechanics Theoretical Minimum and I agree with bhobba that it is excellent.
 
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