DrChinese said:
They most certainly ARE polarization clones of each other. And they are entangled. But they are not polarization entangled, which is quite different.
How do we know that they're polarization clones of each other if they don't produce entanglement stats?
Also, if
DrChinese said:
...the only difference in producing the entangled state versus the product state is a small rotation of a wave plate.
That wouldn't seem to indicate that they're "quite different", unless we are to assume that a "small rotation of a wave plate" somehow switches on some sort of action at a distance or ftl communication between the photons.
DrChinese said:
If we accept your physical assumption of "counter-propagating influences", then these should produce the same statistics as entangled particles. But they don't.
The fact that a wave plate rotation is required to produce polarization entanglement would seem to indicate that they weren't clones of each other to begin with. Or, maybe the wave plate rotation keeps them cloned but adjusts some other parameter which then results in entanglement. Or, maybe the wave plate rotation unclones them, and then, since they're uncloned they have to communicate via action at a distance or ftl to be 'entangled'.
DrChinese said:
Now why are these particles acting different? Because they are NOT in a superposition of polarization states. This is meaningful within QM but has no counterpart in a local realistic theory - in which there is no such thing as a superposition (by definition).
I think we both agree that (1) quantum superposition and quantum entanglement can't be understood in terms of separable (factorable) combinations of the individual systems. However, contrary to (1), (2) Bell (via a certain interpretation of the scope of EPR's definition of reality) has required LR models of entanglement to be represented in a separable form which contradicts the reality of the experimental situations to which that form is being applied. The paper that you referenced agrees with (1). So does every other paper I've read on this. I haven't found anything yet that specifially addresses (2), except for viable LR models that, in agreement with (1), encode the fact that joint detection is determined by different parameters than those which determine individual results -- but, according to you, we can't accept those because their predictions agree with qm and experiments.
By the way, thanks for the reference. My 'assertion' wrt a simplified 'realistic' view of the underlying optical disturbances is probably much too simplistic. It does seem to work for entangled photons produced by atomic cascades though. I'm just beginning a study of OPDC. So, my little simplification might turn out to be ridiculous.
Here's another paper (you've probably read it) that some viewers might be interested in. There's lots of good stuff at Sergienko's group's website.
http://people.bu.edu/alexserg/PRL3893_1993.pdf
Einstein-Podolsky-Rosen-Bohm Experiment Using Pairs of Light Quanta Produced by Type-II Parametric Down-Conversion
Authors:T.E. Kiess, Y.H. Shih, A.V. Sergienko, and C.O. Alley
Phys. Rev. Lett. v.71, pp. 3893-3897 (1993)
So far I don't find anybody saying that the correlations are due to action at a distance or ftl. Eg., in the paper referenced below, they define nonlocality rather innocuously (and in fact state that action at a distance isn't indicated). I think this might be the way that lots (most?) physicists think about it. Quantum nonlocality doesn't mean nonlocality. (The first link might time out, so I included a link to the preprint version.)
http://qopt.postech.ac.kr/publications/PhysRevA-60-p2685.pdf
http://arxiv.org/PS_cache/quant-ph/pdf/9811/9811060v1.pdf
Experimental study of a photon as a subsystem of an entangled two-photon state
Authors: Dmitry V. Strekalov, Yoon-Ho Kim, Yanhua Shih
Phys. Rev. A v.60, pp. 2685-2688 (1999)
DrChinese said:
The fact is that entangled particles have attributes that do not follow a local realistic explanation.
Only wrt Bell's LR model. Which we know doesn't fit the requirements of the experimental situation.
Considering the small experimental differences necessary for entanglement vs nonentanglement stats, and the fact that even LR models conforming to Bell's restrictions aren't that far away from qm predictions, and the fact that there are viable LR models that don't conform to Bell's restrictions, all support the idea that the 'problem of nonlocality' has to do with the way things are being talked about, and not anything to do with the existence of action at a distance or ftl anything.
DrChinese said:
Talk to Bell about this. Or God. I did not create our universe, so it is not my requirement. Next you will be complaining about the 4 color map theorem as being "inane".
The 4 color map theorem is logically rigorous. Bell's assessment of the form that an LR model of entanglement must take isn't.
Anyway, the requirement than any LR model in any form be incorrect is your requirement. You've been shown LR models whose predictions agree with those of qm and experimental results -- and your response is that you want them to produce a dataset that disagrees with qm and experimental results.
I know how you got there (there's only one way -- Bell's way), but wouldn't it make sense to at least look at them and evaluate whether they're realistic and/or local instead of dismissing them because they're quantitatively correct?
I'm going to keep my Bell talk to a minimum for the time being. You've opened up a whole new world for me with the OPDC stuff, and I feel compelled to learn as much about it as I can. (Hmmmm, maybe there is a method to your madness.) Anyway, thanks again.