B What Happens to a Cat in a Box Without Factorization?

[cube137]

With that in mind why do you still think its an issue?

Thanks
Bill

By narrowing or limiting it to interpretations where they are not an issue. then they are not an issue? But remember we are searching for unification of quantum mechanics and spacetime and there is a possibility these are emergent. Then it's good idea to decompose the problem.. that is.. State Vector + Additional Postulates = Factorizations = Observations. Then perhaps we can think of experiments that can remove the additional postulates.. this will suppressed factorizations and make objects disappear from physical world and remaining only as state vectors in some dimensions. Why do you categorically discount this possibility? Axiom of QM is observation. But if it is emergent. Then observation could be emergent. Perhaps we can state Bohm Implicate Order is the domain of the State Vector.. then the additional Postulate is what bring about the Explicate Order (physical world). Is this reasoning not technically incorrect? I'll write this in an article so need to know if the distinctions and problems are basically correct.

 

[bhobba]

By narrowing or limiting it to interpretations where they are not an issue. then they are not an issue? .

Your logic is confused. There is one issue and one issue only - the one I said right at the start:

Don't be confused by the factorisation issue - it's not what some make it out to be. Its not that a quantum system can't be factored into cats etc, its that decoherence MAY depend on that factorisation. As yet theorems are lacking to decide the issue one way or another. It's a very fringe issue - and for good reason - similar assumptions are made in many areas of physics and it would be silly to think that are all 'wrong'. I remember one discussion on it where it was shown even classical mechanics has the problem - but few would doubt that branch of science in its domain of applicability.

It does not depend on interpretation, but is more worrisome in MW because it does not have the concept of observation which defines a particular factorisation.

However, these days, as I explained, MW is formulated in terms of Histories so the above is not an issue. The statement 'Moreover, replacing “systems” with, say, “coarse grainings” does not seem to help at all' is wrong. Coarse grainings are histories. The fact is it can be rigorously formulated that way.

That's all there is to it. Nothing more really needs to be said. IMHO the whole thing, as I have stated from the start, is utter BS - not because its not legit - but people blow it all out of proportion IMHO.

If my view is still unclear I will have leave it there because I can't explain it any better. You can wade through the large number of long threads about it if you want to see more discussion, but IMHO they pretty much go nowhere.

Thanks
Bill

 

[cube137]

Can others elaborate on this? Is hbobba 100% correct?

The idea is State Vector + Additional Postulate = Factorizations -> Observations
If Additional Postulate = Consciousness
Then State Vector + Consciousness = Factorizations -> Observations

In Copenhagen, it is popular prior to 1980s that observation can collapse wave function. Modern view of decoherence removes consciousness completely from QM as observers can be stray photons. So I want to write in the article is that Decoherence didn't entirely remove Consciousness in Copenhagen... the modern Decoherence just makes consciousness an even bigger role.. that it *MAY* be the additional postulate that must be added to State Vector to produce Factorizations and Observations. Can others please comment if this idea is technically incorrect and why?

 

[bhobba]

In Copenhagen, it is popular prior to 1980s that observation can collapse wave function.

That has always been the view of Copenhagen

So I want to write in the article is that Decoherence didn't entirely remove Consciousness in Copenhagen...

It never has required conciousness. You are thinking of Von-Neumann's interpretation which is very backwater these days. Before delving into conciousness being involved you need to study Von Neumann's seminal text - Mathematical Foundations of Quantum Mechanics where why he introduced it is explained. If you are writing an article about it then such is a must. You will hopefully see how decoherence rendered the reason a non issue.

What has happened in modern times is we have interpretations now where decoherence is central. One is Decoherent Histories where QM is the stochastic theory of histories. There is no concept of observation in its foundations:
http://arxiv.org/abs/gr-qc/9407040
'This is an approach to standard quantum theory specifically designed to apply to genuinely closed systems, up to and including the entire universe. It does not depend on an assumed separation of classical and quantum domains, on notions of measurement, or on collapse of the wave function. Its primary aim is to find sets of histories for closed systems exhibiting negligble interference, and therefore, to which probabilities may be assigned.'

All MW is, in its modern formulation, is Decoherent Histories where each history is interpreted as a separate world. Because of that, that paper IMHO is a non issue.

Thanks
Bill

 

[cube137]

In the article. I can write that consciousness was never required in Copenhagen and only in von_Neuman which is backwatered these days.

However to make State Vector in a certain MWI interpretation consistent with Factorizations where it is NOT formulated in terms of Histories. Consciousness came back in full force nowadays as it may be the additional postulate in the following:

"The idea is State Vector + Additional Postulate = Factorizations -> Observations
If Additional Postulate = Consciousness
Then State Vector + Consciousness = Factorizations -> Observations

It threatened your classical based Ensemble view but the above is technically not incorrect at least for MWI that is formulated NOT in terms of histories. Are we in agreement now? If observation is emergent.. your reasoning about axiom of QM being observation can be superseded by a more superior theory.

 

[bhobba]

In the article. I can write that consciousness was never required in Copenhagen and only in von_Neuman which is backwatered these days.

If you are writing an article on it you need to research it yourself:
https://www.physicsforums.com/threads/wave-function-factorization.853104/page-2#post-5351167
'During an observation, the system must interact with a laboratory device. When that device makes a measurement, the wave function of the systems is said to collapse, or irreversibly reduce to an eigenstate of the observable that is registered'
https://en.wikipedia.org/wiki/Von_Neumann–Wigner_interpretation
'The von Neumann–Wigner interpretation, also described as "consciousness causes collapse [of the wave function]", is an interpretation of quantum mechanics in which consciousness is postulated to be necessary for the completion of the process of quantum measurement.'

However to make State Vector in a certain MWI interpretation consistent with Factorizations

That makes no sense. Once you understand what a state vector means, and what a factorisation is then its obvious it makes no sense.

Here is a state vector factored into observer and what's being observed - |a> is the state of the observer |b> is the state being observed

c|a>|b> + c2|b>|a>.

They are entangled - but the state is well defined.

I think you need to actually study QM. The following would be a good start that stresses interpretation::
http://quantum.phys.cmu.edu/CQT/index.html

Don't skip any of the chapters - closely study them all.

Post here if you have any queries.

Thanks
Bill

 

[cube137]

If you are wrting an article on it you need to reserch oit yourself:
https://www.physicsforums.com/threads/wave-function-factorization.853104/page-2#post-5351167
'During an observation, the system must interact with a laboratory device. When that device makes a measurement, the wave function of the systems is said to collapse, or irreversibly reduce to an eigenstate of the observable that is registered'
https://en.wikipedia.org/wiki/Von_Neumann–Wigner_interpretation
'The von Neumann–Wigner interpretation, also described as "consciousness causes collapse [of the wave function]", is an interpretation of quantum mechanics in which consciousness is postulated to be necessary for the completion of the process of quantum measurement.'
That makes no sense. Once you understand what a state vector means, and what a factorisation is then its obvious it makes no sense.

Here is a state vector factored into observer and what's being observed - |a> is the state of the observer |b> is the state being observed

c|a>|b> + c2|b>|a>.

They are entangled - but the state is well defined.

I think you need to actually study QM. The following would be a good start that stresses interpretation::
http://quantum.phys.cmu.edu/CQT/index.html

Don't skip any of the chapters - closely study them all.

Post here if you have any queries.

Thanks
Bill

All these inquiries are related to Tegmark's stuff. See his stuff at https://medium.com/the-physics-arxi...lid-a-liquid-or-a-gas-5e7ed624986d#.o6ywvpc12:

"Finally, Tegmark uses this new way of thinking about consciousness as a lens through which to study one of the fundamental problems of quantum mechanics known as the quantum factorisation problem.

This arises because quantum mechanics describes the entire universe using three mathematical entities: an object known as a Hamiltonian that describes the total energy of the system; a density matrix that describes the relationship between all the quantum states in the system; and Schrodinger’s equation which describes how these things change with time.

The problem is that when the entire universe is described in these terms, there are an infinite number of mathematical solutions that include all possible quantum mechanical outcomes and many other even more exotic possibilities.

So the problem is why we perceive the universe as the semi-classical, three dimensional world that is so familiar. When we look at a glass of iced water, we perceive the liquid and the solid ice cubes as independent things even though they are intimately linked as part of the same system. How does this happen? Out of all possible outcomes, why do we perceive this solution?"

Bill. Tegmark stuff is what I'm driving at. Are you hostile to the idea because you are an Ensembler? Or do you acknowledge what he stated are not incorrect? If so, it can be summarized in the form of:

State Vector + Additional Postulate = Factorizations -> Observations

If the above is wrong. What terms do you need to use to be compatible with Tegmark stuff?

 

[bhobba]

All these inquiries are related to Tegmark's stuff. See his stuff at https://medium.com/the-physics-arxi...lid-a-liquid-or-a-gas-5e7ed624986d#.o6ywvpc12:

Tegmark is well known to hold rather controversial views.

'For as long as the discipline has existed, physicists have been reluctant to discuss consciousness, considering it a topic for quacks and charlatans. Indeed, the mere mention of the ‘c’ word could ruin careers.'

It ruined Von Neumann's career all right - he is remembered as an utter quack . Same with Penrose who holds even more extreme views.

Instead of reading fringe stuff like Tegmark study the real deal - you will learn a lot more. And you will be able to evaluate claims of those like Tegmark in a more informed way. I remember reading something by him on Quantum Suicide - sensationalist rot came to mind.

I am cold to his stuff because its IMHO rot couched in half truths.

Thanks
Bill

 

[bhobba]

When we look at a glass of iced water, we perceive the liquid and the solid ice cubes as independent things even though they are intimately linked as part of the same system. How does this happen? Out of all possible outcomes, why do we perceive this solution?"

Errrr - maybe because its objectively like that. Just a thought. In fact that is the view of most physicists.

Thanks
Bill

 

[cube137]

Errrr - maybe because its objectively like that. Just a thought. In fact that is the view of most physicists.

Thanks
Bill

I think the simple fact or distinctions is that you treat QM as about probabilities while other physicists treat QM as having more ontology. Is this accurate descriptions? So I'd keep the distinctions in mind and remember your reactions and views is because you are an Ensembler and Tegmark being a QM Ontologist and there is no right and wrong among you. Are you in agreement with this?

 

[bhobba]

I think the simple fact or distinctions is that you treat QM as about probabilities while other physicists treat QM as having more ontology. Is this accurate descriptions?

I think before delving into interpretations you need to understand the formalism. Most interpretations are simply arguments about the meaning of probability:
http://math.ucr.edu/home/baez/bayes.html

So understand the formalism then you can see what's going on with interpretations.

As a start cognate on the following:
http://www.scottaaronson.com/democritus/lec9.html

Once you understand that then you can discuss what it means.

Thanks
Bill

 

[cube137]

That's incorrect.

Any interpretation contains the QM formalism. And from that formalism alone deoherence occurs and the cat is dead or alive.

Don't be confused by the factorisation issue - it's not what some make it out to be. Its not that a quantum system can't be factored into cats etc, its that decoherence MAY depend on that factorisation. As yet theorems are lacking to decide the issue one way or another. It's a very fringe issue - and for good reason - similar assumptions are made in many areas of physics and it would be silly to think that are all 'wrong'. I remember one discussion on it where it was shown even classical mechanics has the problem - but few would doubt that branch of science in its domain of applicability.

Thanks
Bill

First Bill. Thanks a lot for making many points clear (which I couldn't have figured out myself). Being a good mathematician. Can you help settle it once and for all. Can you write the theorem whether changing the factorization would change the results (the same mixed state). How hard to write such theorem? As encouragement, the words "Hobba Theorem" or "Bill Theorem" would become part of QM history on par with Bells' Theorem or other great things. Perhaps it is even worthy of Nobel.

 

[Nugatory]

This thread is well past the point of diminishing returns.
Closed.