Are some of the QM predictions actually correct?

Foundations of physics and/or philosophy of physics, and in particular, posts on unresolved or controversial issues

Are some of the QM predictions actually correct?

Postby FrediFizzx » Tue Feb 25, 2020 3:58 pm

I ask this because the Delft data doesn't match some of the quantum mechanical predictions for ++, --, +-, and -+. I get,

++ is about 33 percent
-- is about 34 percent
+- is about 18 percent
-+ is about 15 percent

They should all be closer to 25 percent each according to QM. Of course there isn't much data for Delft so that may be a problem. Has this been checked in other experiments? Does anyone have data for it?
.
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Re: Are some of the QM predictions actually correct?

Postby Joy Christian » Tue Feb 25, 2020 4:24 pm

FrediFizzx wrote:I ask this because the Delft data doesn't match some of the quantum mechanical predictions for ++, --, +-, and -+. I get,

++ is about 33 percent
-- is about 34 percent
+- is about 18 percent
-+ is about 15 percent

They should all be closer to 25 percent each according to QM. Of course there isn't much data for Delft so that may be a problem. Has this been checked in other experiments? Does anyone have data for it?

QM predictions depend on the angles between a and b. They can't be all 25 percent. See equations (4), (5), and (6) of this paper, for example. https://arxiv.org/pdf/1911.11578.pdf.

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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Tue Feb 25, 2020 6:16 pm

Joy Christian wrote:
FrediFizzx wrote:I ask this because the Delft data doesn't match some of the quantum mechanical predictions for ++, --, +-, and -+. I get,

++ is about 33 percent
-- is about 34 percent
+- is about 18 percent
-+ is about 15 percent

They should all be closer to 25 percent each according to QM. Of course there isn't much data for Delft so that may be a problem. Has this been checked in other experiments? Does anyone have data for it?

QM predictions depend on the angles between a and b. They can't be all 25 percent. See equations (4), (5), and (6) of this paper, for example. https://arxiv.org/pdf/1911.11578.pdf.

***

Yes, the QM prediction for many trials is 25 percent each. You have to average over all the angles.

Out[832]= 0.250177
Out[833]= 0.249906
Out[834]= 0.25016
Out[835]= 0.249757

All very close to 25 percent each. You will find those values calculated on the last page of the non-local simulation PDF here,

EPRsims/non-local2.pdf
.
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Wed Feb 26, 2020 12:36 pm

It looks like Adenier and Khrennikov addressed this situation for the Weihs, et al, 1998 experiment here,

https://arxiv.org/abs/quant-ph/0606122
"Is the Fair Sampling Assumption supported by EPR Experiments?"

You can see in Fig.1(a) that the 4 probabilities are not matching QM. I'm wondering if this is actually a deviation from QM by Nature? My latest simulation also has a slight imbalance.
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Re: Are some of the QM predictions actually correct?

Postby gill1109 » Thu Feb 27, 2020 4:34 am

FrediFizzx wrote:I ask this because the Delft data doesn't match some of the quantum mechanical predictions for ++, --, +-, and -+. I get,

++ is about 33 percent
-- is about 34 percent
+- is about 18 percent
-+ is about 15 percent

They should all be closer to 25 percent each according to QM. Of course there isn't much data for Delft so that may be a problem. Has this been checked in other experiments? Does anyone have data for it?
.

The Delft researchers make no claim that they created the singlet state and implemented the conventional "optimal" measurements. The find an S of about 2.4. But anyway, their sample size is so pitifully small that it is not worthwhile to worry too much about it.

Take a look at

Very strong evidence in favor of quantum mechanics and against local hidden variables from a Bayesian analysis
Yanwu Gu, Weijun Li, Michael Evans, and Berthold-Georg Englert
The data of four recent experiments—conducted in Delft, Vienna, Boulder, and Munich with the aim of refuting nonquantum hidden-variables alternatives to the quantum-mechanical description—are evaluated from a Bayesian perspective of what constitutes evidence in statistical data. We find that each of the experiments provides strong, or very strong, evidence in favour of quantum mechanics and against the nonquantum alternatives. This Bayesian analysis supplements the previous non-Bayesian ones, which refuted the alternatives on the basis of small p values but could not support quantum mechanics.

DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf

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.
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Re: Are some of the QM predictions actually correct?

Postby Joy Christian » Thu Feb 27, 2020 6:21 am

Yanwu Gu, Weijun Li, Michael Evans, and Berthold-Georg Englert wrote:
Very strong evidence in favor of quantum mechanics and against local hidden variables from a Bayesian analysis

The result of their experiment may be strong evidence in favor of quantum mechanics, but it has no bearing on local hidden variables because Bell's theorem is simply a mistaken argument.

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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Thu Feb 27, 2020 10:25 am

gill1109 wrote:
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf

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.

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?
.
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Thu Feb 27, 2020 11:34 am

FrediFizzx wrote:
gill1109 wrote:
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf

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.

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".
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Re: Are some of the QM predictions actually correct?

Postby 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.pdf
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.

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/1099-4300/22/3/287
https://arxiv.org/abs/1312.6403
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 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 correlations
Richard 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
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Sat Feb 29, 2020 11:42 am

gill1109 wrote:
FrediFizzx wrote:
FrediFizzx wrote:
gill1109 wrote:
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf
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.

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.

Got it. You can easily tell from the ++ channel that they don't match the QM probability of 1/4. So, I ask again; is this a deviation from QM by Nature? Seems like it might be.
.
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Re: Are some of the QM predictions actually correct?

Postby Joy Christian » Sat Feb 29, 2020 12:29 pm

FrediFizzx wrote:
You can easily tell from the ++ channel that they don't match the QM probability of 1/4. So, I ask again; is this a deviation from QM by Nature? Seems like it might be.

No, it is not. You are mixing up quantum mechanical predictions with averaging over quantum mechanical predictions. As I noted above, quantum mechanics does not predict a probability of 1\4 for all four options. It predicts cos^2 and sin^2 of half angles between the detector directions a and b. The averaging over these angles does predict a probability of 1/4 for each of the four cases, but those are not quantum mechanical predictions. At best, they are post-quantum mechanical manipulations.

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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Sat Feb 29, 2020 1:29 pm

Joy Christian wrote:
FrediFizzx wrote:
You can easily tell from the ++ channel that they don't match the QM probability of 1/4. So, I ask again; is this a deviation from QM by Nature? Seems like it might be.

No, it is not. You are mixing up quantum mechanical predictions with averaging over quantum mechanical predictions. As I noted above, quantum mechanics does not predict a probability of 1\4 for all four options. It predicts cos^2 and sin^2 of half angles between the detector directions a and b. The averaging over these angles does predict a probability of 1/4 for each of the four cases, but those are not quantum mechanical predictions. At best, they are post-quantum mechanical manipulations.
***

Ok, let's run with that for the Delft data. The QM predictions are for the first set with the a and b angle difference at 135 degrees,

++ and -- = 0.426777
+- and -+ = 0.073223

The Delft data gives,

++ = 0.433962
-- = 0.433962
+- = 0.0566038
-+ = 0.0754717

Three of them are closer but one is off quite a bit. I'll do the other 3 angles to see what we get.
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Re: Are some of the QM predictions actually correct?

Postby Joy Christian » Sat Feb 29, 2020 2:02 pm

FrediFizzx wrote:
Joy Christian wrote:
FrediFizzx wrote:
You can easily tell from the ++ channel that they don't match the QM probability of 1/4. So, I ask again; is this a deviation from QM by Nature? Seems like it might be.

No, it is not. You are mixing up quantum mechanical predictions with averaging over quantum mechanical predictions. As I noted above, quantum mechanics does not predict a probability of 1\4 for all four options. It predicts cos^2 and sin^2 of half angles between the detector directions a and b. The averaging over these angles does predict a probability of 1/4 for each of the four cases, but those are not quantum mechanical predictions. At best, they are post-quantum mechanical manipulations.
***

Ok, let's run with that for the Delft data. The QM predictions are for the first set with the a and b angle difference at 135 degrees,

++ and -- = 0.426777
+- and -+ = 0.073223

The Delft data gives,

++ = 0.433962
-- = 0.433962
+- = 0.0566038
-+ = 0.0754717

Three of them are closer but one is off quite a bit. I'll do the other 3 angles to see what we get.

The question is: Is the one that is off an experimental glitch or showing something deeper? Well, if it is something deeper, then all experiments would see the same effect. Do they?

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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Sat Feb 29, 2020 2:18 pm

Joy Christian wrote:
FrediFizzx wrote:
Joy Christian wrote:
FrediFizzx wrote:
You can easily tell from the ++ channel that they don't match the QM probability of 1/4. So, I ask again; is this a deviation from QM by Nature? Seems like it might be.

No, it is not. You are mixing up quantum mechanical predictions with averaging over quantum mechanical predictions. As I noted above, quantum mechanics does not predict a probability of 1\4 for all four options. It predicts cos^2 and sin^2 of half angles between the detector directions a and b. The averaging over these angles does predict a probability of 1/4 for each of the four cases, but those are not quantum mechanical predictions. At best, they are post-quantum mechanical manipulations.
***

Ok, let's run with that for the Delft data. The QM predictions are for the first set with the a and b angle difference at 135 degrees,

++ and -- = 0.426777
+- and -+ = 0.073223

The Delft data gives,

++ = 0.433962
-- = 0.433962
+- = 0.0566038
-+ = 0.0754717

Three of them are closer but one is off quite a bit. I'll do the other 3 angles to see what we get.

The question is: Is the one that is off an experimental glitch or showing something deeper? Well, if it is something deeper, then all experiments would see the same effect. Do they?
***

Well, there isn't much data for Delft so probably to be expected. But I would like to see this same analysis for other experiments. The next two angles, -135 and 225 have the same probabilities. We get for -135,

++ = 0.417722
-- = 0.379747
+- = 0.139241
-+ = 0.0632911

And for 225,

++ = 0.354839
-- = 0.387097
+- = 0.16129
-+ = 0.096774

And for -45 the probabilities are just swapped,

++ and -- = 0.073223
+- and -+ = 0.426777

++ = 0.0784314
-- = 0.117647
+- = 0.392157
-+ = 0.411765

So some are close and some aren't but they do somewhat follow the pattern.
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Sat Feb 29, 2020 8:14 pm

Well, I can do the analysis for the Munich experimental data since they give totals for the runs in their paper here,

https://arxiv.org/abs/1611.04604

But there seems to be a discrepancy between the two tables of combined data of two runs they list on page 28. I'll post the analysis as soon as I figure out what is going on.
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Re: Are some of the QM predictions actually correct?

Postby gill1109 » Sun Mar 01, 2020 2:13 am

FrediFizzx wrote:Well, I can do the analysis for the Munich experimental data since they give totals for the runs in their paper here,
https://arxiv.org/abs/1611.04604
But there seems to be a discrepancy between the two tables of combined data of two runs they list on page 28. I'll post the analysis as soon as I figure out what is going on.

See also
https://rpubs.com/gill1109/OptimizedMunich
https://rpubs.com/gill1109/AdvancedMunich
But I'm afraid this experiment is also too small for any hard conclusion. Like Delft, it is an experiment on two entangled spins, in this case of two rubidium atoms at a distance of 400 metres, brought into entanglement by "entanglement swapping" using measurements on photons at a third location. So they do attempt to create the singlet state, and the traditional measurements! But of course, they will not succeed perfectly. (Vienna and NIST deliberately try to create a much less than maximally entangled state, thanks to the phenomenon discovered by Eberhard (Ph. H. Eberhard, Phys. Rev. A 477-750 (1993)), that less entanglement could give more noise resistance and hence stronger "quantum non-locality".)
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Sun Mar 01, 2020 10:01 am

Here is the Munich results for the first combined table on page 28. The probabilities are the same, 0.426777 and 0.073223 or swapped.

For a, b
++ = 0.111573
-- = 0.115302
+- = 0.375878
-+ = 0.397247

For a, b'
++ = 0.116202
-- = 0.117208
+- = 0.377621
-+ = 0.388969

For a', b
++ = 0.12592
-- = 0.105294
+- = 0.387422
-+ = 0.381364

For a', b'
++ = 0.38421
-- = 0.34958
+- = 0.137666
-+ = 0.128545

I would expect these to be closer to the QM predictions since quite a bit more data but they aren't. However, this data set only gets about 2.085 for CHSH so probably not very entangled.
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Re: Are some of the QM predictions actually correct?

Postby gill1109 » Mon Mar 02, 2020 1:11 am

The "true state" is likely a mixture of the singlet state with the completely random state. See Very strong evidence in favor of quantum mechanics and against local hidden variables from a Bayesian analysis by members of the Singapore group Yanwu Gu, Weijun, Michael Evans, and Berthold-Georg Englert, which I have referred to a number of times before.
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf
In their section V part A, they describe their prior assumptions about the state, assuming QM. A mixture of a rank one density matrix with a completely mixed state. Unfortunately, they do not tell us what their maximum a posteriori probability estimate of the state is, under the QM assumptions; they just show that it is very very much more likely than the a posteriori most likely LR model. As far as I can see, they assume that the (traditional CHSH optimal) measurements were implemented perfectly.
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Re: Are some of the QM predictions actually correct?

Postby FrediFizzx » Mon Mar 02, 2020 11:48 am

gill1109 wrote:The "true state" is likely a mixture of the singlet state with the completely random state. See Very strong evidence in favor of quantum mechanics and against local hidden variables from a Bayesian analysis by members of the Singapore group Yanwu Gu, Weijun, Michael Evans, and Berthold-Georg Englert, which I have referred to a number of times before.
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf
In their section V part A, they describe their prior assumptions about the state, assuming QM. A mixture of a rank one density matrix with a completely mixed state. Unfortunately, they do not tell us what their maximum a posteriori probability estimate of the state is, under the QM assumptions; they just show that it is very very much more likely than the a posteriori most likely LR model. As far as I can see, they assume that the (traditional CHSH optimal) measurements were implemented perfectly.

Yeah, that is where I got the info for Munich from. I don't care about their comparison to local-realistic as we already know that is completely wrong. Has anyone done a better analysis of what I am looking for? The QM probabilities for ++, --, +- and -+.
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Re: Are some of the QM predictions actually correct?

Postby gill1109 » Tue Mar 03, 2020 2:59 am

FrediFizzx wrote:
gill1109 wrote:The "true state" is likely a mixture of the singlet state with the completely random state. See Very strong evidence in favor of quantum mechanics and against local hidden variables from a Bayesian analysis by members of the Singapore group Yanwu Gu, Weijun, Michael Evans, and Berthold-Georg Englert, which I have referred to a number of times before.
DOI: 10.1103/PhysRevA.99.022112
https://arxiv.org/pdf/1808.06863.pdf
In their section V part A, they describe their prior assumptions about the state, assuming QM. A mixture of a rank one density matrix with a completely mixed state. Unfortunately, they do not tell us what their maximum a posteriori probability estimate of the state is, under the QM assumptions; they just show that it is very very much more likely than the a posteriori most likely LR model. As far as I can see, they assume that the (traditional CHSH optimal) measurements were implemented perfectly.

Yeah, that is where I got the info for Munich from. I don't care about their comparison to local-realistic as we already know that is completely wrong. Has anyone done a better analysis of what I am looking for? The QM probabilities for ++, --, +- and -+.

Not as far as I know, sorry. Maybe I will try myself, one of these days... I can try to get hold of Gu et al's software and adapt it to come up with some best estimates. Or just ask Gu himself.
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