- #106
fleem
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So if you want a thread moved to philosophy, simply add a troll post and BOING its in the philosophy forum. My how kind of the moderators to give trolls such power!
fleem said:So if you want a thread moved to philosophy, simply add a troll post and BOING its in the philosophy forum. My how kind of the moderators to give trolls such power!
zenith8 said:Where's the troll post?
If you're referring to the experiment I suggested at the end of my last technical post - then it is a real experiment suggested in a peer-reviewed journal - see p. 3072 of the article "Quantum phenomena in terms of energy-momentum transfer" in J. Phys. A: Math. Gen. 32, 3069 (1999) and many subsequent follow-ups.
See also "Manipulating atoms with photons", Cohen-Tannoudji and Dalibard in "The new physics of the 21st century" ed. G Fraser, Cambridge University Press (2005).
fleem said:My point is that even if a moderator believes some posts are philosophizing, the moderator should still be hesitant to move the thread to the philosophy forum, because otherwise trolls can easily manipulate the forums. This point is important because it proves the mistake of moving this thread to philosophy without having to debate how much philosophizing was actually occurring within this thread (since surely no one believes it was excessive... I hope). Certainly a thread with obvious excessive philosophizing and little or no science, should be moved. That wasn't the case here.
zenith8 said:You're completely missing the point. Because - in the matter-wave optics experiments - we find that it is possible to diffract, reflect, focus, interfere, do stimulated emission with the wave field in question (that is mathematically represented by the wave function) then that is experimental evidence for the objective existence of the wave. If the wave can be subject to and utilized in such a process, it logically follows that the wave field must exist in order to act and be acted upon.
WaveJumper said:Yes, i concede that it appears you are right. The problem with the cat(or should i say cats) re-surfaces and is back in full swing.
I mean that "spooky action at a distance" exists solely as a speculative metaphysical explanation for quantum entanglement correlations.ajw1 said:I assume you mean that no proven physical process has been found for the nonlocal effects and the 'spooky action at a distance'.
Afaik, standard QM doesn't use 'collapse of the wavefunction' to refer to speculative occurances in the quantum realm underlying instrumental behavior. It refers to changes in the objective experimental situation following qualitative instrumental results.ajw1 said:In my opinion if one accepts that the Bell experiment supports the standard QM interpretation then both 'Nonlocality' as well as 'spooky action at a distance' have been proven experimentally. For me these words refer to the same process that is called 'collapse of wave function forcing entangled particles to take a stand' in classic QM. In this sense 'spooky action at a distance' is also just a name, no explanation at al.
Nonlocality, like any metaphysical speculation, is only a consideration if one assumes that the possibility of its existence is well supported. In my view, it isn't.ajw1 said:I think the important conclusion is that one should not suggest that this problem has been solved, as some of the earliest posts in this topic did. It is only solved by ignoring ontological questions or taking one of the (unproved) interpretations for granted.
It has a nice ring to it, however I believe in and like to speculate about the deeper reality underlying instrumental behavior. While science is limited to the sensory realm, instrumental behavior provides the basis for many good assumptions about deeper reality which might then become the basis for more realistic theories.zenith8 said:So you're a fundamentalist instrumentalist (far too many syllables for a job description).
The assumption of nonlocality in nature isn't warranted vis standard qm -- and the passage from the Stanford Encyclopedia of Philosophy (concerning standard qm) that you quoted supports this.zenith8 said:... I fail to see why you are using the instrumentalist Orthodox interpretation of QM to make sweeping statements about the physical reality of 'action at a distance', and to justify writing 'Incorrect. Incorrect.' next to perfectly correct statements of fact in my original post #36.
There are levels of reality. Our mode of existence is somewhat limiting. We all agree that there's a deeper reality. When we offer qualitative descriptions of that deeper reality, then we're engaging in speculative metaphysics because there's no way to completely objectify the descriptions themselves. The only things that are amenable to objectification are the instrumental behaviors predicted by the quantitative theory.zenith8 said:The main difference of opinion seems to be that you think that 'realistic' means 'engaging in speculative metaphysics' rather than 'objectively existing' ...
It is, somewhat. Speculative physics involves formulating testable hypotheses. Metaphysical speculations are, by definition, nontestable -- though they can still be evaluated as more or less reasonable.zenith8 said:... and that 'metaphysics' appears to be some sort of term of abuse.
FAPP we can. If the level of reality wrt which objective distinctions are made (instrumental predictions) produces no distinction, then as far as the science is concerned there's no distinction.zenith8 said:We cannot accept, as a legitimate argument form, inferences from the unobservability of a distinction to the unreality of the distinction.
I don't understand what you're saying here.fleem said:We find nothing spooky about a pair of local particles transferring information (energy, particles, virtual photons) without regard to causality because we consider such interactions as occurring instantaneously, and we learned from the classical world that where there is no time there is no "sequence of events", and where there is no sequence of events there is no causality. In studying entanglement we've discovered the exact same thing can apply to particles that we presume through classical laws are some distance apart from each other, as long as we do not attempt to measure the space-time interval between them. Specifically, it can happen as long as there are no events at each end of that presumed space-time interval. So this should lead us to realize that a space-time interval doesn't exist unless there are events at each end. Specifically, it is those events that define the space-time we're so used to measuring classically (macroscopically).
ThomasT said:I don't understand what you're saying here.
This seems to be the heart of our difference in opinion. If this would be correct the results of the experiment could not be used to support the predictions made by orthodox QM. Furthermore there would be no reason for all the hard work done by http://www.physorg.com/pdf132830327.pdf" .ThomasT said:The statistical dependence has a local causal explanation vis experimental design and execution.
ajw1 said:This seems to be the heart of our difference in opinion. If this would be correct the results of the experiment could not be used to support the predictions made by orthodox QM. Furthermore there would be no reason for all the hard work done by http://www.physorg.com/pdf132830327.pdf" .
A local causal explanation is a local hidden variable explanation. Of course de Bell experiments might have flaws, but the common view is that hidden variables are excluded by the experiment.
Maybe a bit off-track, but very interesting: If the experiments suggests the De Broglie waves are real, are there any theories/indications about what might be waving?zenith8 said:"Perhaps the most convincing proof of the reality of the quantum world would be to capture some of its creatures and hold them in place for all to see. This has become feasible." [Ho-Kim et al., 2004]
Clear evidence for the existence of the wave field (which is mathematically represented by the wave function) comes from the modern development of matter wave optics. In ultracold atomic gases the speed of the atoms is so slow that the de Broglie wavelength of an atom is approximately equal to the spacing between individual atoms. The atoms then have a dominant wave behaviour that allows manipulation by laboratory atom-optical devices. Although the matter wave (i.e. wave field) is not directly observable, the fact that significant quantities of matter can be diffracted, focussed, reflected, etc using essentially optical devices is clear evidence that wave fields are physically real.
Also 'matter wave amplification' experiments give further evidence for the existence of wave fields i.e. production of an output of atoms with particular properties from a Bose-Einstein condensate reservoir of atoms in a trap using a process similar to stimulated emission of light in a laser. If the wave can be subject to and utilized in such a process, it logically follows that the wave field must exist in order to act and be acted upon.
ajw1 said:If we accept for now that the Bell experiment isn't flawed and the data from the experiments suggest that some FTL action appears to happen, are there any experiments that support one of the ontological interpretations mentioned in this topic?
Maybe a bit off-tack, but very interesting: If the experiments suggests the De Broglie waves are real, are there any theories/indications about what might be waving?
p.s. Do you recommend Quantum Causality from Peter Riggs for futher reading? Looks interesting to me.
ThomasT said:The statistical dependence has a local causal explanation vis experimental design and execution.
ajw1 said:This seems to be the heart of our difference in opinion.
meopemuk said:sokrates,
I guess their idea is that the wave function is some kind of material "fluid", that superposition of states is a real thing, and that wavefunction's collapse is an objective physical process.
Why not? QM accurately predicts the outcomes of Bell experiments no matter how Bell is interpreted.ajw1 said:If this would be correct the results of the experiment could not be used to support the predictions made by orthodox QM.
“The significance of our experiment lies entirely in achieving space-like separation, even under the assumption that a quantum measurement is only finished after a macroscopic mass has moved, as in the Penrose-Diosi model,” Zbinden explained.ajw1 said:Furthermore there would be no reason for all the hard work done by http://www.physorg.com/pdf132830327.pdf" .
An intuitive understanding of the statistical dependencies and the correlations as being locally caused, which is what we have without the inference of nonlocality vis Bell, isn't quite the same as a local hidden variable explanation.ajw1 said:A local causal explanation is a local hidden variable explanation.
The lhv formulation on which experimentally violated inequalities are based is incompatible with the experimental designs which produce entanglement. The incompatibility has to do with the locality condition which is, sufficiently, a statistical independence condition.ajw1 said:Of course de Bell experiments might have flaws, but the common view is that hidden variables are excluded by the experiment.
Yes, but it wouldn't say anything conclusive between orthodox QM interpretation and any local hidden variable theoryThomasT said:Why not? QM accurately predicts the outcomes of Bell experiments no matter how Bell is interpreted.
The referenced article also contains the quoteThomasT said:“The significance of our experiment lies entirely in achieving space-like separation, even under the assumption that a quantum measurement is only finished after a macroscopic mass has moved, as in the Penrose-Diosi model,” Zbinden explained.
Bell experiments usually advance the state of the art. They're valuable for that reason alone.
ThomasT said:An intuitive understanding of the statistical dependencies and the correlations as being locally caused, which is what we have without the inference of nonlocality vis Bell, isn't quite the same as a local hidden variable explanation.
The lhv formulation on which experimentally violated inequalities are based is incompatible with the experimental designs which produce entanglement. The incompatibility has to do with the locality condition which is, sufficiently, a statistical independence condition.
Bell's analysis doesn't exclude lhv formulations. Lhv formulations are compatible with qm wrt the prediction of individual detections (the rates are predictable, the sequences are random). The CI goes a bit deeper in saying that, assuming locality, hidden variable descriptions are excluded due to foundational principles of quantum theory which emerge from the assumption of the existence of a fundamental quantum of action.
Interestingly, wrt Bell experiments the hidden variables determining individual detection are irrelevant. Knowing the exact qualitative properties of the separately measured quanta wouldn't alter the joint probabilities, because the joint probabilities depend only on assumptions (based on local causality) already embodied in the standard qm models. That is, it's only the relationship between the separately measured quanta that matters.
ThomasT said:An intuitive understanding of the statistical dependencies and the correlations as being locally caused, which is what we have without the inference of nonlocality vis Bell, isn't quite the same as a local hidden variable explanation.
ajw1 said:Without any raw data from the experimental setup and results I consider myself incapable of conclusively judge the statistical results of Bell experiments, so you might be right. The thing is that people actually working with these kinds of experiments seem to conclude otherwise.
No. I'm just saying that there's a difference between an intuitive understanding of the statistical dependencies and correlations as being solely due to interactions and transmissions constrained by c, and a formal lhv model.RUTA said:Are you pointing out the distinction between separability and locality a la Howard?
ThomasT said:No. I'm just saying that there's a difference between an intuitive understanding of the statistical dependencies and correlations as being solely due to interactions and transmissions constrained by c, and a formal lhv model.
A real contradiction between our intuitive local causal view and standard qm hasn't been definitively established.
sokrates said:PlayUK, Welcome to PF...
Murray Gell-Mann gives an analogy I like a lot when interpreting "spooky action at a distance":
Professor X has a peculiar habit, he puts on a BLUE sock and a RED sock every day instead of wearing identical pairs like normal people. The foot he chooses to put on these socks, however, is random. Therefore one day he could put on a blue sock on his right foot,but the other day he could do just the opposite. You, as the observant student, cannot know which color will end up in which foot before seeing one of his feet (and no complicated theory will help you predict that because it's really random), but once you see one of his socks, you immediately know the color of the sock you didn't see. There's no mechanism, no spooky action at a distance, when you see the the blue sock, you KNOW where the red sock is.
This is Gell-Mann's interpretation (I think it's originally attributed to someone else but I can't remember it now) and could be found in his book "The Quark and the Jaguar" . So if anybody is going to attack this with their own view on the subject, MGM is the man to talk to.
But I have a feeling his interpretation would be far more convincing than any other that I'll ever see in this forum.
PlayUK said:I suppose what I really want to know is how does photon A "connect with" photon B,
ThomasT said:No. I'm just saying that there's a difference between an intuitive understanding of the statistical dependencies and correlations as being solely due to interactions and transmissions constrained by c, and a formal lhv model.
A real contradiction between our intuitive local causal view and standard qm hasn't been definitively established.
pallidin said:Now, that's a serious statement! Nice job!
pallidin said:Now, that's a serious statement! Nice job!
zenith8 said:Hi Pallidin,
OK just to check you have understood ThomasT's idea (and to help slow people like me) here's an exercise for you:
Can you re-explain ThomasT's statement to us - using different words to him as far as you can - and tell us why you think it might be true? (Imagine we're all idiots if it'll help).
Cheers,
Zenith
WaveJumper said:I thought Pallidin was disagreeing with ThomasT's statement.
Anyway, i keep on thinking that we've reached a time when we have to embrace the idea that our inherent classical logic and reasoning of spatial differentation is not a proper picture of how the universe is, in trying to understand how non-local effects can manifest in a local universe. Pretty mind-bending but i suppose that's how if was when the Earth was declared round.
I at first thought that pallidin was being facetious. But on reading his last post, maybe not. In any case, there's nothing particularly bold about my assertions (or conjectures).ajw1 said:How is that a nice job? I haven't seen any evidence for this statement so far. And again: articles on this subject all confirm the nonlocal behaviour for entangled particles.
@ThomasT, do you have any reference supporting your statement?