by gill1109 » Sat Feb 29, 2020 2:11 am
FrediFizzx wrote:FrediFizzx wrote:gill1109 wrote:…
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdfThe authors show that the data fits well to QM with a tensor product Hilbert space with two 2 dimensional components, and an entangled state, but not pure.
After scanning the paper quickly, it looks like they don't match the QM prediction for the 4 probabilities either just like Delft and Weihs, et al. I've printed it out and will study more thoroughly. So is the imbalance due to not maximumly entangled source states or is it a deviation from QM by Nature?
Ok, they didn't actually study what I am talking about and they should have. They studied "no detection" instead of "up and down".
You should think of the Vienna and Nist experiments as traditional polarisation-of-photons based experiments. In such experiments there were two detectors in each wing of the experiment, corresponding to the two output beams of a polarizing beam splitter. The outcomes of both would be click, or no detection. If the experiment is good, you almost never have a click in both detectors in one wing of the experiment. The novelty of the new experiments is to simply scrap one of the two detectors in each wing of the experiment. On each side you now have either "click" or "no-detection".
Delft and Munich are experiments on pairs of spins. So the outcomes are "up", "down". The novelty here is that there is post-selection at a third location, where photons from the two spins meet one another and interfere with one another. The process called entanglement swapping ensures (in theory) that if the two photons both are detected in appropriate detectors *after* having interfered with one another, the two spins are in an entangled state with one another, though they never actually interacted with one another physically.
BTW, My paper on the spinning bi-coloured disk has now come out.
https://www.mdpi.com/1099-4300/22/3/287https://arxiv.org/abs/1312.6403It includes a short discussion of Tim Palmer's research direction (fractals, chaos, p-adic analysis...). There are other short remarks on the connection with loophole models such as Tony Croft's model - basically they are based on tri-coloured spinning disks. The arXiv *abstract* is better than the official published one (a lot shorter!). Notice that
I exhibit a classical system with definitely stronger correlations than the singlet correlations yet reproducing all the important features of the negative cosine ... except its smoothness and/or monotonicity. Nice open problems for the mathematically inclined...!
The triangle wave versus the cosine: How classical systems can optimally approximate EPR-B correlationsRichard D. Gill
(Submitted on 22 Dec 2013 (v1), last revised 17 Feb 2020 (this version, v5))
The famous singlet correlations of a composite quantum system consisting of two spatially separated components exhibit notable features of two kinds. The first kind consists of striking certainty relations: perfect correlation and perfect anti-correlation in certain settings. The second kind consists of a number of symmetries, in particular, invariance under rotation, as well as invariance under exchange of components, parity, or chirality. In this note, I investigate the class of correlation functions that can be generated by classical composite physical systems when we restrict attention to systems which reproduce the certainty relations exactly, and for which the rotational invariance of the correlation function is the manifestation of rotational invariance of the underlying classical physics. I call such correlation functions classical EPR-B correlations. It turns out that the other three (binary) symmetries can then be obtained "for free": they are exhibited by the correlation function, and can be imposed on the underlying physics by adding an underlying randomisation level. We end up with a simple probabilistic description of all possible classical EPR-B correlations in terms of a "spinning coloured disk" model, and a research programme: describe these functions in a concise analytic way. We survey open problems, and we show that the widespread idea that "quantum correlations are more extreme than classical physics allows" is at best highly inaccurate, through giving a concrete example of a classical correlation which satisfies all the symmetries and all the certainty relations and which exceeds the quantum correlations over a whole range of settings
[quote="FrediFizzx"][quote="FrediFizzx"][quote="gill1109"]…
DOI: 10.1103/PhysRevA.99.022112
[url]https://arxiv.org/pdf/1808.06863.pdf[/url]
The authors show that the data fits well to QM with a tensor product Hilbert space with two 2 dimensional components, and an entangled state, but not pure.[/quote]
After scanning the paper quickly, it looks like they don't match the QM prediction for the 4 probabilities either just like Delft and Weihs, et al. I've printed it out and will study more thoroughly. So is the imbalance due to not maximumly entangled source states or is it a deviation from QM by Nature?[/quote]
Ok, they didn't actually study what I am talking about and they should have. They studied "no detection" instead of "up and down".[/quote]
You should think of the Vienna and Nist experiments as traditional polarisation-of-photons based experiments. In such experiments there were two detectors in each wing of the experiment, corresponding to the two output beams of a polarizing beam splitter. The outcomes of both would be click, or no detection. If the experiment is good, you almost never have a click in both detectors in one wing of the experiment. The novelty of the new experiments is to simply scrap one of the two detectors in each wing of the experiment. On each side you now have either "click" or "no-detection".
Delft and Munich are experiments on pairs of spins. So the outcomes are "up", "down". The novelty here is that there is post-selection at a third location, where photons from the two spins meet one another and interfere with one another. The process called entanglement swapping ensures (in theory) that if the two photons both are detected in appropriate detectors *after* having interfered with one another, the two spins are in an entangled state with one another, though they never actually interacted with one another physically.
BTW, My paper on the spinning bi-coloured disk has now come out.
[url]https://www.mdpi.com/1099-4300/22/3/287[/url]
[url]https://arxiv.org/abs/1312.6403[/url]
It includes a short discussion of Tim Palmer's research direction (fractals, chaos, p-adic analysis...). There are other short remarks on the connection with loophole models such as Tony Croft's model - basically they are based on tri-coloured spinning disks. The arXiv *abstract* is better than the official published one (a lot shorter!). Notice that [b]I exhibit a classical system with definitely stronger correlations than the singlet correlations yet reproducing all the important features of the negative cosine [/b]... except its smoothness and/or monotonicity. Nice open problems for the mathematically inclined...!
[i]The triangle wave versus the cosine: How classical systems can optimally approximate EPR-B correlations[/i]
Richard D. Gill
(Submitted on 22 Dec 2013 (v1), last revised 17 Feb 2020 (this version, v5))
[quote]The famous singlet correlations of a composite quantum system consisting of two spatially separated components exhibit notable features of two kinds. The first kind consists of striking certainty relations: perfect correlation and perfect anti-correlation in certain settings. The second kind consists of a number of symmetries, in particular, invariance under rotation, as well as invariance under exchange of components, parity, or chirality. In this note, I investigate the class of correlation functions that can be generated by classical composite physical systems when we restrict attention to systems which reproduce the certainty relations exactly, and for which the rotational invariance of the correlation function is the manifestation of rotational invariance of the underlying classical physics. I call such correlation functions classical EPR-B correlations. It turns out that the other three (binary) symmetries can then be obtained "for free": they are exhibited by the correlation function, and can be imposed on the underlying physics by adding an underlying randomisation level. We end up with a simple probabilistic description of all possible classical EPR-B correlations in terms of a "spinning coloured disk" model, and a research programme: describe these functions in a concise analytic way. We survey open problems, and we show that the widespread idea that "quantum correlations are more extreme than classical physics allows" is at best highly inaccurate, through giving a concrete example of a classical correlation which satisfies all the symmetries and all the certainty relations and which exceeds the quantum correlations over a whole range of settings[/quote]