Quantum Mechanics without Measurement

atyy

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Oh... and another point... what makes you think that these frameworks are incompatible?
There are always incompatible frameworks, so we can just pick framework 2 to be one which is incompatible with framework 1.
 
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There are always incompatible frameworks, so we can just pick framework 2 to be one which is incompatible with framework 1.
That's not true. This problem doesn't arise in the classical world. The entire classical world can be divided into any number of frameworks, all of which are compatible.

Incompatible frameworks only arise when certain quantum properties of a system are described based upon them.
 
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stevendaryl

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But if I am using framework 2, then I cannot use framework 1. But I must use framework 1 to know I am using framework 2.
That doesn't make any sense to me. Look, right now, I'm typing at a computer. I don't need a framework to tell me that. I could use a framework to answer the question: "What is the probability that I would be typing at a keyboard at time t1, given that such and such was true at time t0?"

The framework that I'm typing about may have nothing to do with the question of the probability that I would be typing at a keyboard. I don't have to live on the moon in order to compute what the surface gravity would be.
 

atyy

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That doesn't make any sense to me. Look, right now, I'm typing at a computer. I don't need a framework to tell me that. I could use a framework to answer the question: "What is the probability that I would be typing at a keyboard at time t1, given that such and such was true at time t0?"

The framework that I'm typing about may have nothing to do with the question of the probability that I would be typing at a keyboard. I don't have to live on the moon in order to compute what the surface gravity would be.
But that means that the statement "I am typing at a computer" is a statement that is real, even though it is not a statement in any framework.
 

stevendaryl

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But that means that the statement "I am typing at a computer" is a statement that is real, even though it is not a statement in any framework.
Why do you say that? A framework is a set of possible histories. "I am typing at a computer" is a possible history. So there is a framework in which that is a possible history.

Anyway, I don't see why you think there is any difference between "I am typing at a computer" and "I am typing at a computer, trying to figure out probabilities according to framework [itex]\mathcal{F}_2[/itex]". If the first can be "real", then so can the second.

What do you think "Using framework [itex]\mathcal{F}_2[/itex]" means? To me, it means that I'm trying to solve a particular mathematics problem, which is to compute probabilities for a particular set of histories, using the rules of quantum mechanics. None of those histories have to be "real" for me to be able to do that calculation. None of them have to be about me.
 

atyy

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Why do you say that? A framework is a set of possible histories. "I am typing at a computer" is a possible history. So there is a framework in which that is a possible history.
I wrote "But that means that the statement "I am typing at a computer" is a statement that is real, even though it is not a statement in any framework. " in response to "Look, right now, I'm typing at a computer. I don't need a framework to tell me that."

Anyway, I don't see why you think there is any difference between "I am typing at a computer" and "I am typing at a computer, trying to figure out probabilities according to framework [itex]\mathcal{F}_2[/itex]". If the first can be "real", then so can the second.
There's a difference, because "I am typing at a computer" makes sense in one framework. However, "I am using framework 2" makes sense only in framework 1.

What do you think "Using framework [itex]\mathcal{F}_2[/itex]" means? To me, it means that I'm trying to solve a particular mathematics problem, which is to compute probabilities for a particular set of histories, using the rules of quantum mechanics. None of those histories have to be "real" for me to be able to do that calculation.
A framework is just a classical stochastic process, so in that framework, one history is real each time you "run the experiment".

None of them have to be about me.
But can they be about me? If they cannot, then the measurement problem is not solved.
 
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But can they be about me? If they cannot, then the measurement problem is not solved.
Can you define yourself in terms of particle properties? If so, then sure, you can use CH to describe yourself.

At least the classical part of you, will fit into a single framework and all frameworks for the measurements you make on quantum systems will be compatible with it, but not necessarily with each other.

Does CH address why observers can only make probablistic predictions on quantum systems, despite unitary evolution of their wavefunctions? Nope. It offers nothing on this subject.

You'll need to turn to dBB or MWI and interpretations related to it for that one.
 
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DevilsAvocado

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You keep interpreting what people are saying as "questioning Bell". Nobody questions the theorem, and nobody questions the predictions of quantum mechanics. The issue is over how to interpret the theorem, and quantum mechanics.
Really? Nobody questions anything? That's weird, how about this:

My original statement was motivated by EPR and Bell's proof, and there I know (because Pitowsky wrote a paper about it) that nonmeasurability can avoid the conclusion.
Nobody questions anything?? Well, it sure looks like you're claiming that there is a possibility to avoid the conclusion of Bell's theorem.

And your friend Pitowsky, is writing papers titled "Resolution of the Einstein-Podolsky-Rosen and Bell Paradoxes", where he claims:

"There is, however, a logical possibility that there is nothing wrong with the locality principle, and the violation of Bell's inequality indicates rather a limitation in the mathematical theory of probability. [...] The purpose of this article is to turn this logical possibility into a physical model that explains the observed frequencies on the basis of the validity of the locality principle."

Problem:
  • Pitowsky never got the Nobel Prize in Physics for his physical Local Realism.

  • Instead, he was refuted on a half page, two months after the publication in 1982, where it is concluded;
    "The inequality shows that the statement is inconsistent with quantum mechanics."
A resolution that uses nonmeasurable sets isn't really going to win any prize money, because constructing a nonmeasurable set is not something you can really do.
So why on earth are you claiming that this "can avoid the conclusion", when it's completely meaningless??

It looks like we are walking on a very thin line here, and so called "interoperations" that includes words like "LHV", "Classical", "Local Realism", "more natural than QM", etc, is not interpretations but a new theory contradicting QM and Bell's theorem and if the poster can't provide at least one peer reviewed paper, backing up these sensational claims (worth US$1.1 million + instant global fame) with rigorous proofs, well... it's quite clear that this is a violation* of the forum rules.

(Please do not question "the words", I can provide a bunch of quotes & links, but prefer not to, anyone following this thread has seen it several times)

*This is exactly why atty wrote "BTW, not to be discussed in this forum". Get it?

To avoid closure of this thread, my recommendation is that you, or any other, writing about "non-measurable LHV theories", etc, clearly states that this is just a game of words (or in best case mathematics), that has nothing to do with Bell's theorem and real science. I can guarantee you that there are other readers of this thread that knows less about these things than you and me, and they will get the wrong picture, and we are not supposed to contribute to this kind of confusion in this forum.

Thanks.
 

stevendaryl

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I wrote "But that means that the statement "I am typing at a computer" is a statement that is real, even though it is not a statement in any framework. " in response to "Look, right now, I'm typing at a computer. I don't need a framework to tell me that."
I don't need a framework to tell me that, but that doesn't mean that it isn't included as a part of a framework.

A framework is just a classical stochastic process, so in that framework, one history is real each time you "run the experiment".
The sense in which a framework is a classical stochastic process is just that there is a set of possible histories, and there is a way to compute probabilities for any history in the set. There isn't necessarily a notion of "real" or of "running the experiment".


But can they be about me? If they cannot, then the measurement problem is not solved.
Sure. Histories can be about you, to the extent that we can say that you are a quantum system and your states correspond to projection operators.
 

stevendaryl

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Really? Nobody questions anything? That's weird, how about this:
That isn't questioning Bell's theorem. A theorem always has assumptions and a conclusion. It's valid if it is impossible for the assumptions to be true and the conclusion to be false. Nobody here is questioning the validity of Bell's theorem (I'm not saying that nobody does, but nobody in this thread). The issue is exactly what are the assumptions that the theorem relies on, and is it possible to construct a model that doesn't make those assumptions.

"There is, however, a logical possibility that there is nothing wrong with the locality principle, and the violation of Bell's inequality indicates rather a limitation in the mathematical theory of probability. [...] The purpose of this article is to turn this logical possibility into a physical model that explains the observed frequencies on the basis of the validity of the locality principle."
Yeah, he identified that Bell's theorem implicitly makes assumptions about measurability, and Pitowsky's model doesn't satisfy those assumptions.

Problem:
  • Pitowsky never got the Nobel Prize in Physics for his physical Local Realism.


  • The Nobel Prize is never given for something that speculative. It was a toy model.
 

stevendaryl

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It looks like we are walking on a very thin line here, and so called "interoperations" that includes words like "LHV", "Classical", "Local Realism", "more natural than QM", etc, is not interpretations but a new theory contradicting QM and Bell's theorem and if the poster can't provide at least one peer reviewed paper, backing up these sensational claims (worth US$1.1 million + instant global fame) with rigorous proofs, well... it's quite clear that this is a violation* of the forum rules.
It seems that you are accusing me of things that I haven't said. You are saying that Pitowsky's article has this character? Pitowsky responded to the article you linked to, although it cost me $25 to see the response.

To avoid closure of this thread, my recommendation is that you, or any other, writing about "non-measurable LHV theories", etc, clearly states that this is just a game of words (or in best case mathematics), that has nothing to do with Bell's theorem and real science.
I don't agree with that, but I will not protest, if you want to close the thread.
 

berkeman

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Thread closed for Moderation...
 

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