What does the probabilistic interpretation of QM claim?

  • #76
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The trouble I find with "corpuscular interpretation" is that it's invariably like an
Esher drawing; -- it makes sense when you focus only on pieces of the picture,
but becomes nonsense when viewed as a whole.
I like your analogy with Esher drawings, but I don't find it troubling. To the contrary, I find this controversy rather neat. The point is that in experiments we cannot see the entire drawing (=the entire world). We always see one particular aspect of it. One piece of Esher's stair. For example, we measure either momentum or position of a particle, but not both of them together. So, I agree that when we try to imagine the whole drawing in our brain, we find it controversial. But I don't see any particular reason why nature should care about the deficiencies of our imagination. Perhaps, it is impossible to make a full coherent mental picture of the world. So what? The important thing is that there are no contradictions in our (limited) experimental studies of the world. And corpuscular interpretation of quantum mechanics satisfies this requirement. Everything that goes beyond boundaries of experiment is equal to philosophy/religion and has no place at science discussion forums.

Eugene.
 
  • #77
strangerep
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I don't think that my views are much different from those of Ballentine. If I remember correctly, Ballentine is associating the idea of *quantum state* with an ensemble of identically prepared systems. He was being careful not to focus on individual events/measurements. But if we do consider such individual events/measurements, we have no other choice but to conclude that modern quantum mechanics cannot say anything definite about them. These events/measurements are governed by pure chance. I don't see anything wrong with it, and actually like this idea.
Now if only you would re-read Ballentine and adopt the mainstream meaning of
the term "collapse" explained therein (i.e., abandon your private meaning of that
term), much miscommunication would be avoided. :-)

Of course, one may take the point of view (shared by Einstein and, if I understand correctly, by Dr. Neumaier) that quantum mechanics is not a complete/final theory.
That there should be some field-based deterministic approach, [...]
I'll let Arnold speak for himself, but I understand Arnold's position to be that
orthodox quantum theory can be more rationally understood using a field picture,
which is a different statement from the above.

BTW, it doesn't hurt to remind people occasionally that the usual Bell theorems
speaking against certain hidden variable theories do not go through in general for
infinite numbers of hidden variables. One integrates over these variables, in an
expression like:

[tex]
\int d\lambda_1 \, d\lambda_2 \dots d\lambda_n
[/tex]

where the [tex]\lambda_i[/tex] denote the hidden variables.
For infinite n, the measure in the integral is ill-defined.

And field theories tend to have an infinite number of degrees of freedom ...
 
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  • #78
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Bit of a tangent but I read an article about them having closed all the loop holes in Bell's recently. Which of course made the scientists become ever more clever with their loopholes. There are only one or two left now that haven't been filled in by experiment and I suspect they will become ever more absurd as they are closed, or more bizarrely correct even! :biggrin:

http://www.newscientist.com/article/mg20928011.100-reality-check-closing-the-quantum-loopholes.html

Subscription only I'm afraid, although there is a taster:

Can the universe really be as weird as quantum theory suggests? Ingenious experiments are coming close to settling the issue

WHEN Rupert Ursin stood in the darkness at the highest point of La Palma in the Canary Islands he found it scary. "Really scary," he says. It was less the blackness stretching out towards the Atlantic Ocean some 15 kilometres away. It was more the sheer technical challenge ahead- and perhaps just a little because of the ghosts he was attempting to lay to rest.

Ursin and his colleagues from the Institute for Quantum Optics and Quantum Information in Vienna, Austria, were there that night to see if they could beam single photons of light to the 1-metre aperture of a telescope on the island of Tenerife, 144 kilometres away. Even on a fine day, when Teide, Tenerife's volcanic peak, is clearly visible from La Palma, that would ...
I know its not strictly apropo of anything but I thought it was an interesting article anyway.

Seems the God of the gaps is perhaps existing in smaller gaps, or is he..?
 
  • #79
strangerep
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[...] corpuscular interpretation of quantum mechanics
satisfies this requirement [of explaining our (limited) experimental studies of the world]
It doesn't explain the observed wave-like behavior.

(Sigh. This after I swore to myself I wouldn't get embroiled in a
wave-particle debate. Time to exit.)
 
  • #80
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0
BTW, it doesn't hurt to remind people occasionally that the usual Bell theorems
speaking against certain hidden variable theories do not go through in general for
infinite numbers of hidden variables. One integrates over these variables, in an
expression like:

[tex]
\int d\lambda_1 \, d\lambda_2 \dots d\lambda_n
[/tex]

where the [tex]\lambda_i[/tex] denote the hidden variables.
For infinite n, the measure in the integral is ill-defined.

And field theories tend to have an infinite number of degrees of freedom ...
How is this of any predictive of qualitative use though to science?

It's all very well invoking infinities but they really just say that anything can or could happen and that just isn't really conceptually or scientifically viable. There must be a theory that has a value that would produce a result that is within the bounds of reality. Infinity forgoes such a utility even in the wave function.

I'm pretty sure that even in physics the infinite is a limit that is merely defined as the expanse or x of the entire universe.

How are you defining the limit in this equation as all there can be, or anything that you can think of? And does it really mean anything further than say Copenhagen if you do? If not ultimately where is the utility, isn't it just semantics like MWI, ie ultimately indistinguishable.

I'm not saying you may be wrong I am merely saying that this does not distinguish itself and can not ultimately from any other interpretation. The depressing vanilla ice cream is hard to ignore or to be distinguished from.

It doesn't matter what you believe, if ultimately it will never be more than faith, then one God is as good as another god.

I find it kind of depressing that reality is not deterministically predictive, or even qualitative, but what if it just isn't?
 
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  • #81
strangerep
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How is this of any predictive of qualitative use though to science?
Quantum field theory is the most accurately predictive theory we know.

How are you defining the limit in this equation as all there can be,
or anything that you can think of?
I was pointing out a restriction in the applicability of a mathematical theorem,
which is often overlooked, nothing more.
 
  • #82
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0
Quantum field theory is the most accurately predictive theory we know.
I'm not talking about field theory I am talking about how you define infinity. Are we renormalising, using infinity or just chaos? How would you prove any of them had any underlying reality anyway regardless of mathematical form?

Is maths even suited to this problem?


I was pointing out a restriction in the applicability of a mathematical theorem,
which is often overlooked, nothing more.
Yes and I was agreeing, however in terms of interpretation how do we even know that our maths is even apt?

Bohr in particular said that we might have to accept that we simply neither have the language or maths to explain reality as yet. Perhaps its a comprehension issue, can we see the wood for the trees? And if one of them falls over does it make a sound. :wink:

Is it because the only way to make sense of reality is to come to a deterministic point in evolution of mind which then makes us only able to understand a mappable theory, and if so does that mean that we are not even able to comprehend reality and that ultimately it is not definable by such terms.

All good philosophical questions.

Ultimately the only thing we have is experiment, if this is flawed by our perception then maybe we need to evolve both scientifically and physically? Perhaps we need an alien perspective. Or just some evidence. :smile:

I wasn't at odds with what you are saying I was merely adding an angle.
 
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  • #83
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I find it kind of depressing that reality is not deterministically predictive, or even qualitative, but what if it just isn't?
I actually find it not depressing but cheerful. If reality is random, as I believe it is, then this relieves us from the necessity to dig deeper for explanations. Random things do not require explanations, because they are ... simply random. So, the seemingly never-ending history of science, in which questions "why?" were answered just to be followed by even deeper questions "why?" has possibly come to an end. So, quantum mechanics could be the natural end of our scientific quest. We have lost our ability to ask "why?" Because the only remaining sensible answer is "I don't know". Kind of neat!

Eugene.
 
  • #84
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0
I actually find it not depressing but cheerful. If reality is random, as I believe it is, then this relieves us from the necessity to dig deeper for explanations. Random things do not require explanations, because they are ... simply random. So, the seemingly never-ending history of science, in which questions "why?" were answered just to be followed by even deeper questions "why?" has possibly come to an end. So, quantum mechanics could be the natural end of our scientific quest. We have lost our ability to ask "why?" Because the only remaining sensible answer is "I don't know". Kind of neat!

Eugene.
And you don't find that frustrating?

Science is dead long live Cartesian dualism.

Matter of taste I guess. :smile:
 
  • #85
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49
Quantum field theory is the most accurately predictive theory we know.
Except for the missing description of time evolution. https://www.physicsforums.com/showthread.php?t=476412[/URL] (I hope Dr. Neumaier wouldn't notice this post as he would vehemently disagree.)

Eugene.
 
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  • #86
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And you don't find that frustrating?
For centuries scientists struggled to find the ultimate answer. Now we found it! Time to celebrate with champagne and caviar and not be depressed.

Eugene.
 
  • #87
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For centuries scientists struggled to find the ultimate answer. Now we found it! Time to celebrate with champagne and caviar and not be depressed.

Eugene.
I'm gonna take coke then if you don't minds, I need a pick me up. I picked a bad day to give up methamphetamine. :wink:
 
  • #88
A. Neumaier
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Except for the missing description of time evolution. https://www.physicsforums.com/showthread.php?t=476412[/URL] (I hope Dr. Neumaier wouldn't notice this post as he would vehemently disagree.)[/QUOTE]
You speak from a position of ignorance about what QFT is and can do.

In the thread [url]https://www.physicsforums.com/showthread.php?t=476412[/url] , I showed that your statement is wrong. But you didn't even find it worth your time to do the little work that would have enabled you to understand my argument and to verify that I am correct.
 
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  • #89
A. Neumaier
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I didn't see where you "explained the experiment by the classical
Maxwell equations" in these slides. (Or are you implicitly referring
to the arguments given in Mandel & Wolf?)
I used the fact the quantum mechanics of a photon is given by the Maxwell equations.
See p.8. Thus the analysis starting p.51 applies verbatim.
It's not clear to me where, in the hidden variable assumptions you
listed, one has assumed point particle structure.
The properties (i)-(iv) characterize what is expected of a classical elmentary particle.
More precisely, they characterize a particle that preserves a classical identity while moving through the beam splitter. Pointlikeness is not essential here - it is just the usual classical model for an elementary particle. But since this seemed to be the cause of your query, I changed the wording and now speak of a ''hidden classical particle assumption''
isnead of a ''hidden point particle assumption''. Thanks for the correction! (The updated version will probably be on the web an hour from now.)
 
  • #90
strangerep
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Is maths even suited to this problem?
[...] in terms of interpretation how do we even know that our maths is even apt?
It's not all-or-nothing.
Maths develops/evolves partly to meet new challenges.

[...]
All good philosophical questions.
Perhaps, but they should probably be taken up in the philosophy forum,
since this seems to be gradually drifting away from the original intent of
this thread.
 
  • #91
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It's not all-or-nothing.
Maths develops/evolves partly to meet new challenges.



Perhaps, but they should probably be taken up in the philosophy forum,
since this seems to be gradually drifting away from the original intent of
this thread.
This is all pure philosophy anyway unless you are going to tell me interpretations now aren't? But yes I was not expecting a discussion on them anyway. They just highlight that mathematically we have no idea if maths even represents anything, just that it appears to inductively reproduce results. The actual maths is pretty much a philosophical representation of something we can't measure, on which we base a philosophical interpretation.
 
  • #92
A. Neumaier
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In my lecture http://www.mat.univie.ac.at/~neum/ms/optslides.pdf , I call this revision the thermal interpretation of quantum mechanics. It does not require the slightest alteration of quantum mechanics or quantum field theory. I only changed the currently accepted weird way of talking about quantum system (a long tradition introduced by many years of brainwashing) into one which matches common sense much better. So it is not a change in the foundations but only a change in the interpretation - one that is more consistent with the mathematics
A discussion forum for discussing the thermal interpretation has been approved:
https://www.physicsforums.com/showthread.php?t=490492
Please post your comments there.
 
  • #93
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Bit of a tangent but I read an article about them having closed all the loop holes in Bell's recently.
There are only one or two left now that haven't been filled in by experiment and I suspect they will become ever more absurd as they are closed, or more bizarrely correct even! :biggrin:
Ah? Not all have been closed, clearly, since you're saying there are a few left lingering.
 

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