SciPhysicsForums.com

gill1109 wrote:The problem (a very common problem with this kind of work) is that reading the text and reading the formulas tells two different stories.

A computer simulation could clear up all questions here. The computer simulation would have to allow the independent user to submit their own sequences of settings, get to see raw experimental data (times and events and types of events), and then analyse that data using their own statistical algorithms. The user could then check the local character of the simulated model by simple tests.

All over science there is a movement toward *reproducible science*. One does not just publish papers with final results but one also publishes data, programs, lab note-books. Independent scientists must be able to replicate experiments, and must get credit for doing such work.

Esail wrote:

Justo wrote:

Esail wrote:Let alpha be the setting of polarizer PA and beta the setting of polarizer PB. Alpha and beta are arbitrary. They cannot be defined by an equation.
We start with the initial photon pair with polarization phi_a = 0° at wing A and phi_b 90° at wing B.
Delta is the angle between the setting of the polarizer and the polarization of the photon.
For wing A we get delta_a = alpha-phi_a = alpha-0° = alpha
If and only if we choose beta = alpha+pi/2 then we get delta_b = alpha+pi/2-90°=alpha again.
Thus equation (8) says for all photons which pass PA at alpha the peer photons pass PB at alpha+pi/2 provided the polarizers are set perpendicular to each other. This is due to the same rules applying to both sides.

I know this is old stuff, but I am trying to understand. Esail says that the initial polarization of photon a is phi_a=0. It seems that after measuring with setting alpha on wing A the polarization changes from 0 to alpha, that's ok, no problem so far. The problem is after measuring on wing A, the initial polarization on wing B changes from 90 to alpha + 90. If this is so, it is a scandalously nonlocal model. Maybe I am not understanding.

Correct, you didn't understand. Pls read the text carefully. There is no change of polarization involved with the initial context before measurement.

Esail wrote:Correct, you didn't understand. Pls read the text carefully. There is no change of polarization involved with the initial context before measurement.

Justo wrote:

Esail wrote:Let alpha be the setting of polarizer PA and beta the setting of polarizer PB. Alpha and beta are arbitrary. They cannot be defined by an equation.
We start with the initial photon pair with polarization phi_a = 0° at wing A and phi_b 90° at wing B.
Delta is the angle between the setting of the polarizer and the polarization of the photon.
For wing A we get delta_a = alpha-phi_a = alpha-0° = alpha
If and only if we choose beta = alpha+pi/2 then we get delta_b = alpha+pi/2-90°=alpha again.
Thus equation (8) says for all photons which pass PA at alpha the peer photons pass PB at alpha+pi/2 provided the polarizers are set perpendicular to each other. This is due to the same rules applying to both sides.

I know this is old stuff, but I am trying to understand. Esail says that the initial polarization of photon a is phi_a=0. It seems that after measuring with setting alpha on wing A the polarization changes from 0 to alpha, that's ok, no problem so far. The problem is after measuring on wing A, the initial polarization on wing B changes from 90 to alpha + 90. If this is so, it is a scandalously nonlocal model. Maybe I am not understanding.

Esail wrote:Let alpha be the setting of polarizer PA and beta the setting of polarizer PB. Alpha and beta are arbitrary. They cannot be defined by an equation.
We start with the initial photon pair with polarization phi_a = 0° at wing A and phi_b 90° at wing B.
Delta is the angle between the setting of the polarizer and the polarization of the photon.
For wing A we get delta_a = alpha-phi_a = alpha-0° = alpha
If and only if we choose beta = alpha+pi/2 then we get delta_b = alpha+pi/2-90°=alpha again.
Thus equation (8) says for all photons which pass PA at alpha the peer photons pass PB at alpha+pi/2 provided the polarizers are set perpendicular to each other. This is due to the same rules applying to both sides.

FrediFizzx wrote:

Esail wrote:

FrediFizzx wrote:
Yeah, and his paper is worse than his weird code. He has A(delta, lambda) and B(delta, lambda) with delta = alpha in both cases. No indication of what beta is even.
.

The polarizer setting was beta = alpha+pi/2. With perpendicular polarizer setting there is 100 % coincidence predicted by the model in the paper in accordance with QM and with experiments.

LOL! If that is the case then your model is 100 percent non-local. What equation number is beta = alpha+pi/2 in the paper or what is it near in the paper? I don't see it.
.

Esail wrote:

FrediFizzx wrote:
Yeah, and his paper is worse than his weird code. He has A(delta, lambda) and B(delta, lambda) with delta = alpha in both cases. No indication of what beta is even.
.

The polarizer setting was beta = alpha+pi/2. With perpendicular polarizer setting there is 100 % coincidence predicted by the model in the paper in accordance with QM and with experiments.

FrediFizzx wrote:
Yeah, and his paper is worse than his weird code. He has A(delta, lambda) and B(delta, lambda) with delta = alpha in both cases. No indication of what beta is even.
.

FrediFizzx wrote:

Heinera wrote:

Esail wrote:It is important to note that the contextual effect is a local effect. Thus the entire model is local. Bell's inequation only applies to non-contextual models.

The fact that you need to know the value of alpha in order to determine the measurement result in wing B, as your code shows, makes the model non-local. This is the very definition of non-local concerning Bell's theorem.

Yeah, and his paper is worse than his weird code. He has A(delta, lambda) and B(delta, lambda) with delta = alpha in both cases. No indication of what beta is even.

Joy Christian wrote:

Esail wrote:
Physically [Bell] only took into account noncontextual models.

This statement is quite wrong. It ignores the history of how Bell arrived at his theorem. In his 1966 paper, which was written before his famous 1964 paper, Bell points out the mistake von Neumann had made regarding the possibility of general non-contextual hidden variable theories. Having done so, Bell then provides a correct theorem that rules out the possibility of any noncontextual theory that can reproduce the predictions of quantum theory. The latter theorem is also independently proved by Kochen & Specker. It is now known as Bell-Kochen-Specker theorem. Thus by the time Bell wrote his famous 1964 paper he was more than aware of the fact that noncontextual models have been ruled out, quite generally, because he was one of the people who had decisively ruled them out! Therefore his famous theorem of 1964 explicitly considers contextual hidden variable models and claims that, while contextual models are still possible [albite Bell does not use this language because Shimony had not yet introduced the word "contextual" in the literature on Bell's theorem], any such realistic model must be nonlocal (or remotely contextual). Thus it is quite wrong to claim that "physically [Bell] only took into account noncontextual models." On the contrary, Bell explicitly considered contextual models.

Heinera wrote:

Esail wrote:It is important to note that the contextual effect is a local effect. Thus the entire model is local. Bell's inequation only applies to non-contextual models.

The fact that you need to know the value of alpha in order to determine the measurement result in wing B, as your code shows, makes the model non-local. This is the very definition of non-local concerning Bell's theorem.

Esail wrote:It is important to note that the contextual effect is a local effect. Thus the entire model is local. Bell's inequation only applies to non-contextual models.

Joy Christian wrote:I agree with Heinera. I doubt that anyone else apart from Esail would see the described model as local.

***

Esail wrote:

Heinera wrote:

Esail wrote:
If you change alpha you change the selection. This changes the correlation. Now the context comes into play. Measurement results depend on the context. This is defined in MA4 in that the polarization of the photons of a selection is equal to the p-state (polarization angle) of the selection. So if we select alpha on wing A and by this way alpha+pi/2 on wing B we have the polarization alpha+pi/2 of the selected photons on wing B. This can indeed mean that a photon with polarization 90° from the initial state and a particular value of lambda would hit polarizer B at beta. But if we change the context by setting polarizer A at alpha thus having polarization alpha +pi/2 at B the photon with the same value of lambda would possibly not hit B at beta anymore. This is the effect of contextuality. That means we can only speak about measurement values if we add the context in which they appear. In a definite context the measurement values are constant.

In the context of Bell's theorem, this is non-local. Outside of that, it is just ordinary QM.

It is important to note that the contextual effect is a local effect. Thus the entire model is local. Bell's inequation only applies to non-contextual models.

Heinera wrote:

Esail wrote:
If you change alpha you change the selection. This changes the correlation. Now the context comes into play. Measurement results depend on the context. This is defined in MA4 in that the polarization of the photons of a selection is equal to the p-state (polarization angle) of the selection. So if we select alpha on wing A and by this way alpha+pi/2 on wing B we have the polarization alpha+pi/2 of the selected photons on wing B. This can indeed mean that a photon with polarization 90° from the initial state and a particular value of lambda would hit polarizer B at beta. But if we change the context by setting polarizer A at alpha thus having polarization alpha +pi/2 at B the photon with the same value of lambda would possibly not hit B at beta anymore. This is the effect of contextuality. That means we can only speak about measurement values if we add the context in which they appear. In a definite context the measurement values are constant.

In the context of Bell's theorem, this is non-local. Outside of that, it is just ordinary QM.

Esail wrote:
If you change alpha you change the selection. This changes the correlation. Now the context comes into play. Measurement results depend on the context. This is defined in MA4 in that the polarization of the photons of a selection is equal to the p-state (polarization angle) of the selection. So if we select alpha on wing A and by this way alpha+pi/2 on wing B we have the polarization alpha+pi/2 of the selected photons on wing B. This can indeed mean that a photon with polarization 90° from the initial state and a particular value of lambda would hit polarizer B at beta. But if we change the context by setting polarizer A at alpha thus having polarization alpha +pi/2 at B the photon with the same value of lambda would possibly not hit B at beta anymore. This is the effect of contextuality. That means we can only speak about measurement values if we add the context in which they appear. In a definite context the measurement values are constant.

Heinera wrote:

Esail wrote:
What you fail to understand is that the measurement results themselves do not depend on the polarizer position on the other side

But in you pseudocode they do. If I change the value of alpha and keep everything else the same (including the value of lambda), I can get a different measurement result in wing B.

I the measurement result in wing B does not depend on alpha, why is alpha referenced in the code for wing B in the first place?

Joy Christian wrote:The parameter lambda is also not allowed to be non-local. It should not depend, or "know" anything about, the choices of the polarization angles made on either side of the experiment.

***

Esail wrote:
What you fail to understand is that the measurement results themselves do not depend on the polarizer position on the other side

Esail wrote:

Heinera wrote:

Esail wrote:If photons at wing A are selected with alpha the thus selected peer photons at wing B are in state alpha+pi/2 as described in the paper.

Locality means that the result of measurement at wing B should not in any way depend on the setting alpha. Anything else is non-local.

What you fail to understand is that the measurement results themselves do not depend on the polarizer position on the other side, but that the measurement results of a selection depend on the position of the selecting polarizer. Now it is the case that a selection on one wing acts like a selection on the other side with a polarizer that is perpendicular to it on that wing. This is due to the common parameter lambda. In Bell measurements we always consider selections of particle pairs with the same parameter lambda.

Heinera wrote:

Esail wrote:If photons at wing A are selected with alpha the thus selected peer photons at wing B are in state alpha+pi/2 as described in the paper.

Locality means that the result of measurement at wing B should not in any way depend on the setting alpha. Anything else is non-local.