What does the probabilistic interpretation of QM claim?

In summary, the conversation discusses the probability interpretation of quantum mechanics and how it relates to observable operators and measurements. The probability interpretation states that the probability of observing a particular eigenvalue is equal to the square of the state function for that eigenvalue. However, this interpretation does not determine which operators can be measured, as this is a matter of theoretical and experimental developments. The conversation also delves into the issue of measuring position and momentum, and how quantum uncertainty rules out continuity in position. The example of the double-slit experiment is used to demonstrate the wave-mechanics interpretation of position and momentum in quantum mechanics. The conversation ends with a mention of experiments done in strong magnetic fields and how they measure position and momentum in particle tracks.
  • #71
meopemuk said:
I am not so sure why you insist that only 1 electron must be emitted in 100% of cases? What if there is some non-zero probability of 2 or 3 electrons being emitted? I see no problem with that from the point of view of the corpuscular interpretation. This is still something completely different from the continuous charge density field that you are arguing for.

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.

The notion of "corpuscular" entails "discrete, indivisible". This has problems in
explaining wave-like phenomena. (If it's "indivisible", then how did it pass through
both slits...? Blah, blah, blah. I won't repeat that ancient debate which I'm sure
you and everyone around here are thoroughly bored with, and which quantum
theory with Ballentine interpretation explains satisfactorily, imho.)

This is still something completely different from the continuous charge density
field that you are arguing for.

For the record, I'm in favour only of QFT with a minimal statistical interpretation.

EDIT: responding to your edit:

EDIT: Well, if you don't like single electron sources, then we can return to the discussion of interference experiments with single atoms. I hope, you wouldn't deny that individual atoms can be produced one-by-one and that double-slit-type experiments are possible with them?

For a full account, field-theoretic analysis is still necessary.
 
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  • #72
Isn't this a philosophical question though.

I mean what does something claim and what does something prove are mutually exclusive at least in science. :wink:
 
  • #73
Calrid said:
Isn't this a philosophical question though.

I mean what does something claim and what does something prove are mutually exclusive at least in science. :wink:

Could you please include at least a little quoted context so that it's clear
what you're actually replying to??
 
  • #74
strangerep said:
Could you please include at least a little quoted context so that it's clear
what you're actually replying to??

No one so the OP. I am well aware how to use the quote function.

I'm saying that this question probably better suits a philosophical style debate rather than a scientific one as that is what it is.

No science anywhere in interpretation as yet basically. It's all just philosophy isn't it. Not that there is anything wrong with that, especially if you are into strings and branes etc. :smile:

Einstein quoted Descartes, Bohr said Kant was important in his realisation of his interpretation. It has always been a matter of taste what flavour of ice cream you like.

I'm vanilla.
 
  • #75
strangerep said:
... which quantum
theory with Ballentine interpretation explains satisfactorily, imho...

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.

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, which would explain why this particular CCD pixel has fired in this particular instance. Currently such calculations/predictions are impossible. So, we are back to the point where our differences are purely philosophical.

Eugene.
 
  • #76
strangerep said:
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
meopemuk said:
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
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
meopemuk said:
[...] 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
strangerep said:
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
Calrid said:
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
strangerep said:
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
Calrid said:
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
meopemuk said:
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
strangerep said:
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
Calrid said:
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
meopemuk said:
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 going to 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
meopemuk said:
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
strangerep said:
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.
strangerep said:
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
Calrid said:
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
strangerep said:
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 said:
In my lecture http://arnold-neumaier.at/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
Calrid said:
Bit of a tangent but I read an article about them having closed all the loop holes in Bell's recently.

Calrid said:
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.
 
<h2>1. What is the probabilistic interpretation of QM?</h2><p>The probabilistic interpretation of QM is a fundamental principle of quantum mechanics that states that the behavior of particles at the quantum level cannot be predicted with certainty, but only with a certain probability. This means that the outcome of any measurement or observation of a quantum system is not determined, but rather described in terms of probabilities.</p><h2>2. How does the probabilistic interpretation of QM differ from classical mechanics?</h2><p>Classical mechanics, which describes the behavior of macroscopic objects, is based on deterministic principles where the future state of a system can be predicted with certainty. In contrast, the probabilistic interpretation of QM introduces an element of randomness and uncertainty at the quantum level, which is not present in classical mechanics.</p><h2>3. What evidence supports the probabilistic interpretation of QM?</h2><p>There is a wealth of experimental evidence that supports the probabilistic interpretation of QM. For example, the famous double-slit experiment demonstrates the wave-like behavior of particles at the quantum level, which can only be described in terms of probabilities. Additionally, various other experiments have shown that particles can exist in multiple states simultaneously, further supporting the probabilistic nature of quantum mechanics.</p><h2>4. Does the probabilistic interpretation of QM apply to all physical systems?</h2><p>Yes, the probabilistic interpretation of QM applies to all physical systems, regardless of their size or complexity. However, the effects of quantum mechanics are usually only noticeable at the microscopic level, and classical mechanics is still a highly accurate and useful model for describing the behavior of macroscopic objects.</p><h2>5. How does the probabilistic interpretation of QM impact our understanding of reality?</h2><p>The probabilistic interpretation of QM challenges our traditional understanding of reality, as it suggests that the behavior of particles is inherently uncertain and unpredictable. It also raises philosophical questions about the nature of reality and our ability to truly understand and describe it. However, despite its counterintuitive nature, the probabilistic interpretation of QM has been extensively tested and has been shown to be a highly accurate and useful model for describing the behavior of particles at the quantum level.</p>

1. What is the probabilistic interpretation of QM?

The probabilistic interpretation of QM is a fundamental principle of quantum mechanics that states that the behavior of particles at the quantum level cannot be predicted with certainty, but only with a certain probability. This means that the outcome of any measurement or observation of a quantum system is not determined, but rather described in terms of probabilities.

2. How does the probabilistic interpretation of QM differ from classical mechanics?

Classical mechanics, which describes the behavior of macroscopic objects, is based on deterministic principles where the future state of a system can be predicted with certainty. In contrast, the probabilistic interpretation of QM introduces an element of randomness and uncertainty at the quantum level, which is not present in classical mechanics.

3. What evidence supports the probabilistic interpretation of QM?

There is a wealth of experimental evidence that supports the probabilistic interpretation of QM. For example, the famous double-slit experiment demonstrates the wave-like behavior of particles at the quantum level, which can only be described in terms of probabilities. Additionally, various other experiments have shown that particles can exist in multiple states simultaneously, further supporting the probabilistic nature of quantum mechanics.

4. Does the probabilistic interpretation of QM apply to all physical systems?

Yes, the probabilistic interpretation of QM applies to all physical systems, regardless of their size or complexity. However, the effects of quantum mechanics are usually only noticeable at the microscopic level, and classical mechanics is still a highly accurate and useful model for describing the behavior of macroscopic objects.

5. How does the probabilistic interpretation of QM impact our understanding of reality?

The probabilistic interpretation of QM challenges our traditional understanding of reality, as it suggests that the behavior of particles is inherently uncertain and unpredictable. It also raises philosophical questions about the nature of reality and our ability to truly understand and describe it. However, despite its counterintuitive nature, the probabilistic interpretation of QM has been extensively tested and has been shown to be a highly accurate and useful model for describing the behavior of particles at the quantum level.

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