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Why is superdeterminism not the universally accepted explanation of nonlocality? 
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#145
Feb2912, 01:55 PM

P: 1,583




#146
Feb2912, 10:29 PM

P: 1,414

My point is that if the local realist is aware of the historically documented characteristic behavior of light, then he wouldn't expect, in a local deterministic world, a linear correlation between the angular difference of the crossed polarizers and the rate of coincidental detection. He would, rather, expect a nonlinear correlation ... something approximating cos^{2}θ. The fact that Bell inequalities are, more or less, based on formal constraints which require the light in Bell tests to behave in an uncharacteristic way suggests that there's something in those constraints which is not corresponding to Bell test preparation and associated data processing. But not necessarily that nature is nonlocal. 


#147
Feb2912, 10:34 PM

P: 1,583




#148
Feb2912, 10:55 PM

P: 1,414




#149
Feb2912, 10:58 PM

P: 1,583




#150
Feb2912, 11:09 PM

P: 1,414




#151
Feb2912, 11:25 PM

PF Gold
P: 1,376

While I am proponent of local realism I side with DrChinese in this. Have to say that you can have constructive discussions with DrChinese and I am grateful to him as discussions with him have shaped a lot my own understanding about entanglement problem. 


#152
Feb2912, 11:33 PM

PF Gold
P: 1,376




#153
Feb2912, 11:44 PM

PF Gold
P: 1,376




#154
Mar112, 12:16 AM

P: 1,583

(You can, of course, be the fringe type of local realist who has a theory making predictions contrary to QM, but who believes that the only reason the experiments have proven QM right is that they're subject to various flaws, loopholes, and systematic biases. But as Bell tests become more sophisticated, that becomes an increasingly untenable positon, arguably even more so than superdeterminism.) 


#155
Mar112, 12:50 AM

P: 1,583

Presumably you don't disagree with the straightforward math of step 11, so if you reject the conclusion that local realism implies linear correlation you must reject one of the earlier steps. 


#156
Mar112, 01:16 AM

P: 1,414

Do you just mean that the probability of coincidental detection at θ=30 degrees is .75? I think that's what you mean, so lets go with that. But wait, where did that come from? The polarizers were actually set that way, and you noted the result? Right? Ok, so we have a probability of coincidental detection at θ=30 of .75 . Then we set A 30 degrees to the left and B 30 degrees to the right, so now we have a θ of 60 degrees. So now do we do some runs to see what the rate of coincidental detection at θ=60 degrees is, or do we first assume something about what that rate should be? And if we assume something about what that rate should be, then what's that assumption based on? 


#157
Mar112, 01:18 AM

P: 1,583

ThomasT, I define P(θ) in step 2: "A local realist would say that the photon doesn't just randomly go through or not go through the detector oriented at an angle θ; he would say that each unpolarized photon has its own function P(θ) which is guiding it's behavior: it goes through if P(θ)=1 and it doesn't go through it P(θ)=0."
Let's get right to the heart of the matter. If P(30)=P(0) and P(0)=P(30), then P(30) must equal P(30). Thus if P(30) does not equal P(30), either P(30)≠P(0) or P(0)≠P(30) (or both). Since there is a 25% error rate whenever there is a thirty degree seperation, we know that the probabilities that P(30)≠P(0) is 25%, and the probability that P(0)≠P(30) is 25%, and the probability that at least one of these two statements is true is at most 25%+25%=50%. This is not a physical assumption or constraint, it's just math. If event A happens 25% of the time and event B happens 25% of the time, then it's guaranteed that at least 50% of the time neither one of them occurs. If taxis are available in New York City a quarter of the time, and buses are available a quarter of the time, then you know that transportation is available at most 50% of the time. I hope you don't dispute this. 


#158
Mar112, 02:27 AM

P: 1,414




#159
Mar112, 02:42 AM

P: 1,583

As I said, once you've gotten down to step 11 there is no room for argument left, it's just math. If you want to dispute the reasoning you'll have to find an earlier step you disagree with. 


#160
Mar112, 03:27 AM

Sci Advisor
P: 4,612

Lugita15, I would like to see your response to my post #127.



#161
Mar112, 03:27 AM

P: 143

if determinism only is effective within lightcones, in which case if outside eachothers lightcones, a and d could not affect eachother just as future events cannot effect the past, as lightcones expand at the speed of light, if there were particle a that had not yet interacted with other particles d1 d2 dinfinity, (i stated before that this should be impossible under a causally governed universe) in this hypothetical case it would be not practically, but THEORETICALLY impossible to do such an experiment or have such nonlocal effects even without an experiment. also, along with photons a and b traveling in opposite directions, so too will plenty of other EFFECTUAL information be propagated to a and d from particles locally and causally effecting the photon source, so it would make a and d effectively the same as being locally deterministic. it would be determined tho in the universe that the lightcones would eventually expand to make a and d react causally therefore deterministically. 


#162
Mar112, 03:42 AM

P: 1,583

Still, it's a worthwhile task to show that local realism (unless it's superdeterministic) using the conventional definiton cannot reproduce the predictions of quantum mechanics. 


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