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gill1109
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Harrylin: since QM (quantum mechanics) is more general than LR (local realism) how could de Raedt conclude that QM does not fit?
I have not yet studied their paper, and apparently neither did you. However, I don't really understand your question. A single aspect or result of experimental data (even one that had at first not been examined) can in principle disprove a theory.gill1109 said:Harrylin: since QM (quantum mechanics) is more general than LR (local realism) how could de Raedt conclude that QM does not fit?
Addendum: I now wonder if I was mistaken, and that in his last paper De Raedt actually does the very kind of analysis that I was after, but in a different way from what I had in mind. If so, the points 1 and 2 here above merge into a single one.harrylin said:I suppose that everyone participating in this discussion, understands that; so far the easy part! The challenge is here to compare Weihs' data with the two competing models -which include hypotheses/excuses about the physics of the real world.
1. I'm interested in how the models compare for several coincidence windows; it may be sufficient to use the data as presented by De Raedt in his latest paper.
2. De Raedt compares QM with another aspect of the data, from which he concludes that QM does not match the observations. Again it will be interesting to know how successfully that issue can be "explained away", and if his own model fares better or worse.
That's obviously wrong - and not relevant for this discussion. If you want to discuss that idea, please start a topic on it.gill1109 said:[..] Let me say it again in different words. Everything that LR allows, can be mimicked by QM. [..]
I see that one of the models according to b) yields exactly the QM bound; as you studied it, perhaps you can find the answer.gill1109 said:Harrylin: In case of explanation (b), then I wonder why experimenters never see a bigger deviation from the CHSH bound of 2 than the QM bound of 2 sqrt 2. [...]
Interpretation and explanation are almost synonyms. Interpretation a) is certainly a common explanation (with not detectable action but influence at a distance), and I suspect that your variant has no effect on the data analysis here. Nevertheless, explanation a) only refers to obtained measurement data, so I'm afraid that I don't understand your alternative explanation, let's call it a2). Perhaps you can give a peer-reviewed reference to that explanation?I disagree with your interpretation of explanation (a). [..] The so-called influence at a distance only affects [..] the outcomes of measurements which were not performed. [..] QM does not violate the principle that there should be no action at a distance.
Also good. Bell's No.1 refers to "local" explanations of which I mentioned one as explanation b), and no.3 is the common "non-local" explanation that I mentioned as a).gill1109 said:Peer-reviewed reference? How about J. Bell In his "Bertlman's socks" paper? It's one of at least four positions to take.
To be precise, you disagree that 'there is no reality below some "classical level"', means to deny reality below a certain level! But never mind:gill1109 said:I disagree that number 4 denies reality below a certain level.[..]
While local models can be stochastic, Masanes' paper is about nonlocal models but let's call it explanation c). In my next post I'll give a quantitative description belonging to all considered explanations for testing with Weihs' data and I will assume that by design, c) predicts exactly the same as a). If not, please specify.The alternative is to accept the message of QM that nature is irreducibly stochastic.
That is surely a very specious definition of "non-locality" almost not worthy of any attention. Why not simply stick to "violating a Bell inequality", why use the term "non-locality" at all, rather than any other such as "imaginary" or "non-sense"?gill1109 said:Harrylin, you must read Masanes et al. more carefully. Their definition of "non-local" is not the same as yours. By "non-local" they merely mean "violating a Bell inequality".
billschnieder said:That is surely a very specious definition of "non-locality" almost not worthy of any attention. Why not simply stick to "violating a Bell inequality", why use the term "non-locality" at all, rather than any other such as "imaginary" or "non-sense"?
gill1109 said:Bill Schnieder, Gordon Watson: I don't like the terminology either. But: "what's in a name"? It is the *results* of Masanes et al. which are interesting. As for the terminology: this has nowadays become fairly standard in quantum information. Like it or not, it's what people say. It's become a technical term with an established technical meaning.
I now came a little bit further with the possible variation in delay time as function of polarization according to the literature.harrylin said:[..] it will be good to clearly state the main competing explanations for high correlations with small time windows. [..]
common "local-realist" models: no "spooky" influence at a distance, nor wild science fiction.
Strangely enough I know only one such model, of De Raedt et al: influence of polarisation on detection time delay. This influence is inferred from QM predictions as well as from independent experiments, based on an assumed "local-realist" universe. [..]
For further discussion it will be particular interesting to compare De Raedt et al's model against QM (= all the other proposed models, I suppose) with Weihs' data. For that we should know more precisely:
- the basis for the 5%
- the basis for the 30 μs
- the exact formula that De Raedt et al used for their most successful simulations (see the thread on De Raedt's simulations)
- the possible delay time range according to the literature, insofar as this has been observed
- ?
Harald
As there were no comments I will clarify the above: apparently he did not consider the spread in time delays due to the EOM's birefringence. However, that should be done (and could be done!) in order to interpret the experimental findings.harrylin said:I now came a little bit further with the possible variation in delay time as function of polarization according to the literature.
My first suspect in Weih's experiment was birefringence in his photonic crystal. However that was a dead-end road [..] The next obvious suspect is the electro-optic modulator that he used, as these are commonly made of similar materials. [..] What type of electro-optic modulator did he use, and how did he account for its birefringence?
Can someone else perhaps explain this to me?
Hi DrC. "For several years" only in elapsed time. In committed time perhaps a few months. I have to disagree with "deep", though I think the paper I uploaded yesterday is kinda cute for its data visualization, which is different from anything I've seen other people do.DrChinese said:Peter Morgan has been working with the raw Weihs data for several years. He has done some deep analysis of it
Thanks that looks useful!DrChinese said:[..] A graphical presentation of signal delays in the datasets of Weihs et al Peter Morgan (2012)
http://arxiv.org/abs/1207.5775
By any chance, did you also look into the time delay differences due to the EOM's birefringence?Peter Morgan said:[..] I think the paper I uploaded yesterday is kinda cute for its data visualization, which is different from anything I've seen other people do.
I was prompted to post this paper (the computation for which I did about two years ago) to the arXiv by Alejandro Hnilo, whose research group in Argentina has just finished a Bell-type experiment in which they use a pulsed laser. The distances are relatively short, but they record the timings of the laser pulses as well as the timings of Alice's and Bob's measurement events. They have posted their dataset privately, and it may become publicly available in time; they're currently working on their analysis.
harrylin said:By any chance, did you also look into the time delay differences due to the EOM's birefringence?
You may have missed the concern that was perhaps first raised by De Raedt: a certain amount of unaccounted birefringence could explain the results instead of "non-locality". Regretfully nobody seems to know if this may have been caused by the EOM or not.Peter Morgan said:I basically did not much more than what you see in the paper on the arXiv. What looks pretty clear is that a local adjustment can be made to the timings that eliminates the timing features at the nanosecond scale that I at first identified in the longdist35 dataset. I didn't look quantitatively at what might be discovered by looking at multiple datasets (which can become a lot of work, so one wants a relatively strong feeling that it might be worthwhile).
I'm not sure whether the Weihs data contains enough information to characterize what parts of the various timing delays are caused by the electro-optical modulator.
Yeah I know, regretfully my spelling error is in the title and I can't change it.BTW: let's get Gregor Weihs' name right. It's not Weih, nor Weih's. Of course I should feel especially sensitive about this, because there's one place in my arXiv paper where I use Wiehs.