Difference between classic and quantum allowing Bell violation

[James Jr Tankersley]

Question 3 from the mini-conference.

This is the key to why computer simulations can detect quantum vs classic models.

3. What is the difference between classical and quantum allowing to violate Bell? 

Why are computer simulations easily able to detect the difference between classic and quantum models?  Correlations between quantum particle pairs are alway strongly correlated with each other (example: if one is up, the other is down).  But classic particle pairs only appear strongly correlated with each other when the classic particles are "strongly" aligned or anti-aligned with their BPS or GS deflector (example: BPS and classic photon initialized to nearly the same polarity or nearly 90° different polarity). 

Key difference: Classic particle pairs that are "weakly" aligned with their BPS or GS deflector (example: BPS and classic photon polarization differ by nearly 45°) have a near random chance of being detected any particular way, and appear weakly correlated with each other. (example if one particle is detected up, the other still has a near random chance of being detected up or down)

Simplified example in 2D: if the polarization of the BSP (Beam Splitting Polarizer) is 45°, then EPR (classical) photons emitted from the source with polarizations close to 0°, 90°, etc.) have a near equal probability of being detected as either 45° or 135°.

These classic particles (weakly aligned with their polarizer or deflector) will appear weakly correlated (unlike all quantum particle pairs or classical particles pairs wth initial polarizations closely matching or anti-bathing their BPS or GS deflector (strongly aligned with their polarizer or deflector) will appear strongly correlated).

[James Jr Tankersley]

Re-Write (typos fixed - more to the point)

3. What is the difference between classical and quantum allowing to violate Bell? 

Computer simulations detect the difference like this:

Entangled quantum pair particle 2 collapses to a polarity or spin correlated to PBS 1 or SG deflector 1 (same or orthogonal)

While classical pair particle 2 has a polarity or spin correlated to a random value (orthogonal value of what particle 1 was emitted with) and has no relationship with PBS 1 or SG deflector 1.

---- Further detail ----:

Correlations between quantum particle pairs are always measured as strongly correlated with each other. Quantum particle 1 always gains the same or orthogonal polarity of its PBS (Polarizing Beam Splitter) or spin direction of its SG (Stern Gerlach) magnetic deflector. Entangled quantum particle 2 always gains the orthogonal polarity (or spin) as particle 1. Both entangled quantum particles are always measured as strongly correlated with respect to each other and PBS 1 or SG deflector 1.

However correlations between classical particle pairs are not always measured as strongly correlated with each other. Classical particle 1 is emitted from the source with a random polarity (or spin), and its pair particle 2 always has the orthogonal polarity or (spin) of particle 1. Pair particle 2 is orthogonal to the random value of particle 1.

The key difference is that classical pair particle 2 to is orthogonal to a random value, and has no correlation to PBS 1 or SG deflector 1. While quantum pair particle 2 always has the same or orthogonal as PBS 1 or SG deflector 1.

[Jan-Åke Larsson]

See below

Then your "classical pair" cannot reproduce the quantum prediction: opposite outcomes if PBS 1 (SG defl 1) is equally oriented as PBS 2 (SG defl 2).

Your "classical pairs" do not reproduce the quantum predictions. We see the quantum predictions in experiment. Your "classical pairs" then do not describe the experiment well.

Nor can you violate the Bell (CHSH) inequality. If you believe you do, you are doing the calculation wrong.

/Jan-Åke

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Jan-Åke Larsson
Professor, Head of Department

Department of Electrical Engineering SE-581 83 Linköping Phone: +46 (0)13-28 14 68 Mobile: +46 (0)13-28 14 68 Visiting address: Campus Valla, House B, Entr 27, 3A:512 Please visit us at www.liu.se

[James Tankersley Jr]

Hello Jan-Åke,

The simulation does not violate bell with classical particles and perfect detection.

The simulation acts as a confirmation that Bell got the math correct.

Inequalities between classical and quantum particles are clearly detected by simulations with perfect detection.

(The only exception is when we very selectively filter out classic particles that are "least" correlated with their polarizer or deflector. A form of detection loop hole, then we can simulate the false appearance of violating Bell with classical particles)

[Jan-Åke Larsson]

You will still not violate the inequality if you do the calculation correctly.
See for example: Jan-Åke Larsson,  Bell’s inequality and detector inefficiency, Physical Review A 57:3304-3308 (1998)  https://doi.org/10.1103/PhysRevA.57.3304

/JÅ

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[Jan-Åke Larsson]

If you postselect ("very selectively filter out classic particles") you need to adjust the inequality.

The paper can be downloaded from http://liu.diva-portal.org/smash/record.jsf?pid=diva2%3A586507&dswid=8796

/JÅ

On 2023-01-28 20:55, James Tankersley Jr wrote:

Hi Jan-Åke,

I do not appear to have access to your paper, but I am interested in studying it.

It is possible that the simulation math is lacking in some way, though Richard Gill did review and have me make several changes to the software in 2020, but he is not fluent in Java Script to verify claims I was making about the software, I shifted focus, and the review process did not come to a conclusion.

[Jan-Åke Larsson]

Probably better link: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-87169

To view this discussion on the web visit https://groups.google.com/d/msgid/Bell_quantum_foundations/66f64498-115a-0f8f-85a3-16df0f6e8f34%40liu.se.

[James Tankersley Jr]

Does anyone disagree that the following experiment should be expected to do the following?

Conduct actual CHSH experiments with photons pre-polarized to model either QM or Classical.

This should replicate the same results we are seeing in computer simulations. 

QM modelled test:

A. QM photon photon 1 would be pre-polarized to either same as, or orthogonal to PBS 1 (50% chance of one of 2 possible values). 

B. QM entangled photon 2 would be pre-polarized to the opposite of photon 1 (180 degrees different).

C. QM test should have 100% detection of photon 1.  When PBS 2 is same or orthogonal to PBS 1, then photon 2 should also have 100% detection and Bell will be strongly violated. Otherwise photon 2 will have some Malus Filter and Bell will be Does anyone disagree that the following experiment would do the following?

Conduct actual CHSH experiments with photons pre-polarized to model either QM or Classical.

This should replicate the same results we are seeing in computer simulations. 

QM modelled test:

A. QM photon photon 1 would be pre-polarized to either same as, or orthogonal to PBS 1 (50% chance of one of 2 possible values). 

B. QM entangled photon 2 would be pre-polarized to the opposite of photon 1 (180 degrees different).

C. QM test should strongly violate Bell when PBS 1 and PBS 2 are the same or orthogonal and no expected loss. When PBS 2 is neither the same nor orthogonal to PBS 1, then photon 2 should have some Malus Filter loss, but still weakly violate Bell.

Classical modelled test: 

A. Classic photon 1 would be pre-polarized to a random direction (equal chance of any value between 0 and 360 degrees). 

B. Classic pair photon 2 would be pre-polarized to the opposite of photon 1 (180 degrees different).

C. Classic test should expect Malus Filter on both photons (except when photons and PBS are same or orthogonal) and should weakly violate Bell. If detection could be increased to 100%, then Classic should not violate Bell at all (is this possible with electron spin SG tests?).

Classical modelled test: 

A. Classic photon 1 would be pre-polarized to a random direction (equal chance of any value between 0 and 360 degrees). 

B. Classic pair photon 2 would be pre-polarized to the opposite of photon 1 (180 degrees different).

C. Classic test will have Malus Filter on both photons (intrinsic to PBS) and should weakly violate Bell. If detection could be increased to 100%, then Classic should not violate Bell at all (possible with electron spin SG tests?).

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[James Tankersley Jr]

Sorry, resent:

Does anyone disagree that the following experiment should be expected to do the following?

Conduct actual CHSH experiments with photons pre-polarized to model either QM or Classical.

This should replicate the same results we are seeing in computer simulations. 

QM modelled test:

A. QM photon photon 1 would be pre-polarized to either same as, or orthogonal to PBS 1 (50% chance of one of 2 possible values). 

B. QM entangled photon 2 would be pre-polarized to the opposite of photon 1 (180 degrees different).

C. QM test should have 100% detection of photon 1.  When PBS 2 is same or orthogonal to PBS 1, then photon 2 should also have 100% detection and Bell will be strongly violated. Otherwise photon 2 will have some Malus Filter, but still weakly violate Bell.

[James Tankersley Jr]

Draft 3

Does anyone disagree that the following experiment should be expected to do the following?

Conduct actual CHSH experiments with photons pre-polarized to model either QM or Classical.

This should replicate the same results we are seeing in computer simulations. 

QM modelled test:

A. QM photon photon 1 would be pre-polarized to either same as, or orthogonal to PBS 1 (50% chance of one of 2 possible values). 

B. QM entangled photon 2 would be pre-polarized to the opposite of photon 1 (180 [+/- 90] degrees different).

C. QM test should have 100% detection of photon 1.  When PBS 2 is same or orthogonal to PBS 1, then photon 2 should also have 100% detection and Bell will be strongly violated. Otherwise photon 2 will have some Malus Filter, but still weakly violate Bell.

Classical modelled test: 

A. Classic photon 1 would be pre-polarized to a random direction (equal chance of any value between 0 and 360 degrees). 

B. Classic pair photon 2 would be pre-polarized to the opposite of photon 1 (180 [+/- 90] degrees different).

C. Classic test should expect Malus Filter loss on both photons (except when photons and PBS are same or orthogonal) and should weakly violate Bell. If detection could be increased to 100%, then Classic should not violate Bell at all (is this possible with electron spin SG tests [seeing reports of up to 99% efficiency]?).

[Jan-Åke Larsson]

No. The QM test does not work like that. QM tells us that entangled photons are not pre-polarized.

Also, in our experiments, there is no way to "pre-polarize" photon 1 to the "same as, or orthogonal to PBS 1". The PBS orientation is selected so late that no (sub-luminal) signal can ever tell the source what the PBS 1 orientation is going to be.

It is true that the classical model in your example cannot violate the CHSH inequality, the maximal correlation is too low.

Nobody does electron-spin-MZ-experiments, electrons are too sensitive, what people do is atom or ion electronic orbit spin states that are read off through stimulated emission.

/JÅ

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