- #106
DevilsAvocado
Gold Member
- 848
- 91
Nothing?inflector said:... What came first?
Nothing?inflector said:... What came first?
DevilsAvocado said:Nothing?
It probably don’t mean anything (to the discussion), but let’s be finicky, not to create more confusion. In your picture of Double-slit & EPR you state that the superposition is occurring at the screen?? But that’s where the wavefunction collapses (depending on interpretation) = measurement. The superposition of the particle (photon) is when it passes both slits simultaneously.zonde said:We can compare it with double slit experiment:
In interpretation of experiment wave nature of light is completely ignored, insted photons are treated as particles. But if there are two indistinguishable paths for photons treating photons like particles gives wrong result.
Right, this is a BIG question, but no logical laws of physics can demand living observers to start the process of 'reality', because living observers first needs 'reality', to be born!inflector said:I think this is just one of those questions we'll never answer. :-)
Ok, I read the paper. Weihs doesn't contradict what I said any more than Aspect does. Weihs improves on Aspect, but the fact is that the statistical dependencies wrt both are produced via local channels.DrChinese said:It is on my website, and here as well:
http://arxiv.org/abs/quant-ph/9810080
Violation of Bell's inequality under strict Einstein locality conditions
Authors: Gregor Weihs, Thomas Jennewein, Christoph Simon, Harald Weinfurter, Anton Zeilinger
Abstract: We observe strong violation of Bell's inequality in an Einstein, Podolsky and Rosen type experiment with independent observers. Our experiment definitely implements the ideas behind the well known work by Aspect et al. We for the first time fully enforce the condition of locality, a central assumption in the derivation of Bell's theorem. The necessary space-like separation of the observations is achieved by sufficient physical distance between the measurement stations, by ultra-fast and random setting of the analyzers, and by completely independent data registration.
----------------------------------
Let's review what this is saying. Suppose there were a LHV that you proposed. According to Bell, it would need to meet these requirements: a) It makes predictions consistent with experiment; b) It does not violate a Bell Inequality. Clearly,per experiments such as Aspect and many others, a BI is violated. So a) is not possible. Unless...
Now, there is still a possibility that sub-c signalling of detector settings are being communicated between Alice and Bob - which would allow an alternative explanation for the BI violation? With this experiment, however, you can rule that alternative explanation out. They strictly control this so that such signalling is not viable. The essential result was already in the literature, but with this version it rules out any reasonable possibility of another avenue.
inflector said:I think this is just one of those questions we'll never answer. :-) I don't see how we'll ever run the experiment. Something came out of nothing to start it all, or something always existed. One more turtle doesn't help us with answers.
Unless God decides to come out of his slumber and start performing miracles IN FRONT OF science, we'll have to do what we're doing and extrapolate as best we can from the now back as far as we can and see where that takes us.
Science has not proven nonlocality. I'm a physicist who believes the Bell experiments are legit, but these experiments don't prove nonlocality; they prove nonlocality and/or nonseparability. So, it's possible that we have nonseparability and locality.inflector said:As far as nonlocality goes. It sure seems to me that science has proven that, as far as one could at this point. Not that we shouldn't be looking for answers to the crazy questions that arise from this knowledge. But it seems we should accept that as the current understanding absent some new data.
Thanks! That’s okay, I have a donations account at PayPal for stolen quotes.RUTA said:That was a great post! I'm stealing your "nonsenseparability" and "alco-holism" for use in my QM PowerPoint lecture.
It is!RUTA said:I'll cite you, but most people will assume "DevilsAvocado" is just part of the joke :-)
Great, I need some remedy... After your last post, I suffer from posttraumatic brain-expansion...RUTA said:but let me continue along these lines in an effort to give you SOMETHING you can wrap your head around.
Yes! Now we’re getting to "des Pudels Kern"! Let’s take the classical example of a speeding train car. A is onboard and B is standing on the platform:RUTA said:Suppose you have two, entangled, space-like related measurements, A and B. That A and B are "space-like related" means that, per special relativity, in some frames of reference A occurs before B, in some frame of ref A and B are simultaneous, and in other frames of ref B occurs before A. Another way of saying this is a line between A and B would represent a FTL connection. [The combination of these two facts about space-like related events entails, for example, that A cannot be the cause of B unless you believe a cause need not precede its effect or you believe there is a "preferred frame," i.e., one in which A occurs before B.]
Okay! I’m going to be a Philosopher when I grow up, it seem like an easy piece of cake!RUTA said:So, if you don't have "spooky action at a distance" between A and B, there must be a fact of the matter at A, due entirely to the situation in the immediate spacetime vicinity of A to account for your red outcome. QM doesn't give us any way to obtain those "hidden" facts, so it's clearly incomplete. But, violation of the Bell inequality means EPR are wrong, QM is right, so without "spooky action at a distance" the red outcome at A cannot be due to the situation in the immediate spacetime vicinity of A. That's all SEP tells you, really.
You betcha!RUTA said:Since the SEP characterization of nonseparability isn't giving you an ontology to "explain" the red outcome, you're probably saying "WTF?"
Make no mistake about it! I didn’t RESOLVE anything!RUTA said:SEP distilled the mystery of nonseparability from the violations of Bell inequalities by telling us what ISN'T true ontologically, but didn't RESOLVE anything mysterious USING nonseparability!
Please!RUTA said:To do that they need to tell us what IS true ontologically!
Words words words and even more words... "second principle of logic" when & where was this introduce, and what does it mean!? "Your desired ontology" ...is what?RUTA said:Of course, the good philosophers at SEP will simply reply, "We did tell you what IS the case per the second principle of logic, i.e., excluded middle. Your desired ontology is that which we did not exclude in our statement." But, our brains work according to what they say is NOT true, so we just don't have anything left to "see."
This is nothing more than a personal preference, no more, no less.RUTA said:The SEP entry on nonseparability is (overly) simplistically put just saying no "spooky action at a distance,"
Great! One step forward!zonde said:Got it.
I am in "Denial Camp" definitely.
zonde said:Lets say we set out to find what influence two polarizers have on each other and measurements of polarization by them if they are put side by side. Suppose (naturally) we find out that they do not have any detectable effect.
Now encouraged by our result we make another setup where we put two Stern-Gerlach apparatuses side by side and claim that they will not influence each other and respective spin measurements.
Now do I have to explain why this claim will be invalid? I hope not.
Okay! Let’s start with not throwing the logic away in the evaluation of Bell test experiments!zonde said:Who talks about throwing away something really useful? Not me.
ThomasT said:Ok, I read the paper. Weihs doesn't contradict what I said any more than Aspect does. Weihs improves on Aspect, but the fact is that the statistical dependencies wrt both are produced via local channels.
Weihs moves the observers farther apart, varies the polarizer settings via physical random number generator, and does the data matching after all the data is collected rather than on the fly as Aspect does. None of this impacts what I said...
DevilsAvocado said:The above is clear to me. But what I don’t get is how the synchronization of events can 'save' EPR? The "problem" is not whether A performs the measurement before B, or vice versa. The "problem" is that if you have one light-year between A & B – entanglement is still there – and can later be verified if B travels back to A!?
I don’t get this at all...
DevilsAvocado said:Okay! I’m going to be a Philosopher when I grow up, it seem like an easy piece of cake!
"So, if you don't have "spooky action at a distance" between A and B, there must be a fact of the matter at A, due entirely to the situation in the immediate spacetime vicinity of A to account for your red outcome."
EDIT!: I missed this and it makes things even more contradictory...?
"so without "spooky action at a distance" the red outcome at A cannot be due to the situation in the immediate spacetime vicinity of A. That's all SEP tells you, really."And the rest from here... well, doesn’t make any sense... as all the rest...
Seriously, isn’t this what’s it all about!? And didn’t you get it wrong?? All performed Bell test experiments clearly show that it’s impossible to use local 'entities', whether it’s variable or constant – it just doesn’t work, due to the fact that the receiving polarizer’s are randomly rotated *AFTER* the photons left the source...
DevilsAvocado said:Words words words and even more words... "second principle of logic" when & where was this introduce, and what does it mean!?
"Your desired ontology" ...is what?
DevilsAvocado said:I’m honestly thankful that you gave it a try, but seriously RUTA this is not physics – it’s a game of words – to hide all usable facts. And for God’s sake! How do you get this 'fuzzy-logic' into a mathematical formula (so we can start build "nonseparable DVD-players" etc)??
I think that the problem is that you build all this reasoning on this simple assumption:
This is nothing more than a personal preference, no more, no less.
DrChinese said:There are, however, a number of escapes from this: non-locality (BM as already identified), backwards causation (RBW being one) and multiple histories/worlds (MWI) - all of which respect the Main Result by the addition of some wild Escape by our magician, the Amazing Ms. Nature. And note that the Main Result stands, even with the various Escapes! The only remaining question is: by what method did the magician escape? Can you see how the trick is performed?
RUTA said:Thanks for the reference, DrC. I should point out that we don't consider Relational Blockworld (RBW) a backwards causation interpretation. We rather consider it an "acausal" account, meaning the notion of causality is not even valid at the level of QM. We wrote a paper arguing that our acausal account is better than backwards causation accounts: “Why Quantum Mechanics Favors Adynamical and Acausal Interpretations such as Relational Blockworld over Backwardly Causal and Time-Symmetric Rivals,” Michael Silberstein, Michael Cifone & W.M. Stuckey, Studies in History & Philosophy of Modern Physics 39, No. 4, 736 – 751 (2008). http://dx.doi.org/10.1016/j.shpsb.2008.07.005 . If you want to see how this view generates a nonseparable ontology, see “Relational Blockworld: A Path Integral Based Interpretation of Quantum Field Theory,” W.M. Stuckey, Timothy McDevitt & Michael Silberstein, quant-ph/0908.4348 (under review at FoP).
This is important and I have to be sure.RUTA said:Don't confuse locality in the sense of differentiable manifolds (constitutive locality) with the locality of "local hidden variables" in Bell's proof (causal locality). Constitutive locality is associated with separability. Causal locality is "no spooky action at a distance."
Okay, can we 'refine' this and say – According to SEP the 'cause' of EPR is not "spooky action at a distance", it’s 'something else', but SEP can’t say anything about that. (right?)RUTA said:There are three principles of logic: 1) Principle of Identity (A = A), 2) Principle of Excluded Middle (A or not A), and 3) Principle of Non-Contradiction (not (A and not A)). The SEP entry on nonseparability struck me as only providing a nonseparable ontology in the sense of excluded middle, i.e., the ontology you seek is anything that is not X. Now we know what X is, so techically their definition is valid. Unfortunately, that type of definition is only valuable if you have at least ONE example of not X, but most people don't have any examples of not X. For example, if I tell you the color of my chair is not pink, you have lots of possible colors that my chair could be. But, the SEP definition of nonseparability probably doesn't lead you to visualize even one possible nonseparable ontology.
Okay, thanks.RUTA said:I inferred from your post with the SEP definition of nonseparability that you were trying to understand the nonseparability option for avoiding the Bell inequality violations, so I was responding.
No worries mate! It was just a (terribly silly) joke!RUTA said:I'll be glad to continue trying to explain this option to you, but I don't want to cause you physical harm trying to do physics :-)
RUTA said:FTL communication (nonlocality) is one way out of the EPR-Bell paradox. I was simply pointing out that should you opt for that solution, you have a problem with the relativity of simultaneity (RoS). That is, you need A to tell B what happened at A so B can adjust accordingly to make the correlations violate the Bell inequality. But, if that msg from A to B is FTL (A and B are spacelike related), then in some frames B occurs before A (RoS), so you then have to resort to a preferred frame (or allow for effects (B outcome) to proceed their causes (A outcome)). There are advocates for a preferred frame based on violations of the Bell inequality.
DevilsAvocado said:This is important and I have to be sure.
Causal locality
If we set LHV to be +1 & -1 before sending the photons, we are not violating any locality. It’s just a matter of sending away 'predefined letter' in an 'envelope', and we know the outcome in advance, right...?
Constitutive locality
The receivers of the 'envelope' are physically separated in space-time, i.e. they have no connection FTL, right...?
Okay, can we 'refine' this and say – According to SEP the 'cause' of EPR is not "spooky action at a distance", it’s 'something else', but SEP can’t say anything about that. (right?)
Okay, thanks.
No worries mate! It was just a (terribly silly) joke!
>> This is extremely interesting! <<
Wow! I thought we only had one "problem" with the "spooky action at a distance", but this proves it’s much worse2!
Let’s see now... IF we assume there ARE "spooky action at a distance" AND the values of the Particles are 100% RANDOM, and the OTHER Particle must obtain the OPPOSITE value instantly. THIS CAN’T BE DONE DUE TO RoS??
Sweet jeees... I’m feeling dizzy...
Does DrChinese or Frame Dragger or anyone else have a solution to this...?
DevilsAvocado said:This is important and I have to be sure.
Causal locality
If we set LHV to be +1 & -1 before sending the photons, we are not violating any locality. It’s just a matter of sending away 'predefined letter' in an 'envelope', and we know the outcome in advance, right...?
Constitutive locality
The receivers of the 'envelope' are physically separated in space-time, i.e. they have no connection FTL, right...?
Okay, can we 'refine' this and say – According to SEP the 'cause' of EPR is not "spooky action at a distance", it’s 'something else', but SEP can’t say anything about that. (right?)
Okay, thanks.
No worries mate! It was just a (terribly silly) joke!
>> This is extremely interesting! <<
Wow! I thought we only had one "problem" with the "spooky action at a distance", but this proves it’s much worse2!
Let’s see now... IF we assume there ARE "spooky action at a distance" AND the values of the Particles are 100% RANDOM, and the OTHER Particle must obtain the OPPOSITE value instantly. THIS CAN’T BE DONE DUE TO RoS??
Sweet jeees... I’m feeling dizzy...
Does DrChinese or Frame Dragger or anyone else have a solution to this...?
... I need coffee ... or maybe ... a vacation ... in the sun ... something real ... anything ... booze ... girls ...Frame Dragger said:Welcome to the counterintuive nature of QM!
IMO I see a weakness here, "spooky action at a distance" introduces another 'spooky thing' – An instant and universal NOW (that’s probably what made AE want to 'throw up').SpectraCat said:... IOW, if you measure B first, you determine the value of A, if you measure A first, you determine the value of B.
DevilsAvocado said:IMO I see a weakness here, "spooky action at a distance" introduces another 'spooky thing' – An instant and universal NOW (that’s probably what made AE want to 'throw up').
... but that’s maybe the whole solution?? Einstein WAS wrong, there is a universal NOW!?
I dunno...
DevilsAvocado said:IMO I see a weakness here, "spooky action at a distance" introduces another 'spooky thing' – An instant and universal NOW (that’s probably what made AE want to 'throw up').
... but that’s maybe the whole solution?? Einstein WAS wrong, there is a universal NOW!?
I dunno...
Thanks for the info DrC. I continue my reasoning, and relate to some of the 'interpretation issues', in next post.DrChinese said:A lot of the Bohmians believe there is such, a preferred frame. ...
Okay, I think DrC covers the 'basic'.SpectraCat said:No, that is just the same as saying that there is a "preferred reference frame". As RUTA said, there are people exploring that possibility, but I don't think it is necessary to resolve this issue.
Very true! I agree! (with 'some' objections below )SpectraCat said:It is important to realize that this is strictly an interpretational "what is going on behind the scenes" question at this point. AFAIK, there is no way to make any testable predictions based on different theories of *how* the Bell inequality occurs (i.e. how particle A "knows" that a measurement was performed on particle "B").
Okay, I know this is true, but I’m going to 'challenge' you a little (so you can show where I go wrong):SpectraCat said:Most of the problems that are raised in this vein would only be real issues if FTL communication was possible using entangled pairs, but it's not, so we are ok. The causality relationship between the measurements at A and B is one example of this ... if it were somehow possible for Alice to know what Bob was doing at the time she made her measurement (assuming a space-like separation between them), then causality would be a problem, and you could potentially have a logical contradiction, because Alice would have access to information that was not available to all observers, i.e. she would be in a preferred reference frame. But that is equivalent to speculating about how things might change if SR is wrong ... as far as we know it isn't, so let's not worry about all of that .. physics is hard enough to understand as it is .
I agree on the 'interpretation issues', but at the same time – if we cannot describe in fairly simple and understandable words what’s 'going on', and make logical attachments to current understandings – we’re in deep sh*t, IMO.SpectraCat said:To reiterate, from a QM point of view, there are two measurements performed on the members of an entangled pair. Since the results are always perfectly correlated, it fundamentally does not matter which measurement comes first, at least for the purposes of Bell tests.
Well yes, but let’s have a look at the flip side of the coin... Let’s suppose we have arranged a Bell test where the photons run parallel, with a 'photon barrier' between them. Now, after x amount of time the photons hits the polarizer’s. Who is going to decide which one arrives first? The photons!? And if they arrives at exactly the same time (which they should do according to current understanding of physics)? Who is going to do the 'negotiation'?? "The United Council of Photons"?SpectraCat said:All observers in all frames agree on the results of the measurements, once they have communicated them by normal sub-lightspeed channels for comparison.
eveo said:University of Waterloo! That's where I'm off to next year for nanotech engineering :D
Lucky you!eveo said:University of Waterloo! That's where I'm off to next year for nanotech engineering :D
DevilsAvocado said:Okay, I think DrC covers the 'basic'.
Very true! I agree! (with 'some' objections below )
Okay, I know this is true, but I’m going to 'challenge' you a little (so you can show where I go wrong):
Let’s say Bob is a cruel bastard, and Alice is a cat. Bob have arranged a "Schrödinger Box" for Alice so that if the spin is up at Bob, and down at Alice, the "Box" will kill Alice!
Now, it’s hard to argue that Bob don’t know what Alice 'is doing'. He knows if she’s dead or alive...
(of course, Bob cannot control the outcome...)
I agree on the 'interpretation issues', but at the same time – if we cannot describe in fairly simple and understandable words what’s 'going on', and make logical attachments to current understandings – we’re in deep sh*t, IMO.
Well yes, but let’s have a look at the flip side of the coin... Let’s suppose we have arranged a Bell test where the photons run parallel, with a 'photon barrier' between them. Now, after x amount of time the photons hits the polarizer’s. Who is going to decide which one arrives first? The photons!? And if they arrives at exactly the same time (which they should do according to current understanding of physics)? Who is going to do the 'negotiation'?? "The United Council of Photons"?
This is a fairly simple logical problem. Two physically separated entities are going to obtain the opposite outcome 100% random, and ONLY ONE can decide. Who decides? And how is this accomplished on distances FTL?
It does not help if the observers agree. The photons must 'agree' first!
I don’t think this is an 'interpretation issues'. This must be at the 'core' of nature. And I don’t think mixing past, present & future, is going to help us much either.
The answer is most definitely not easy. Just let’s hope it’s logical...
Deepak Kapur said:Is action at a distance possible as envisaged by the EPR Paradox?
Whether the polarizer settings are not varied during a run, or varied nonrandomly, or varied randomly, or varied randomly after emission, the result (the correlation between the angular difference of the polarizers and rate of coincidental detection) doesn't vary.DevilsAvocado said:All performed Bell test experiments clearly show that it’s impossible to use local 'entities', whether it’s variable or constant – it just doesn’t work, due to the fact that the receiving polarizer’s are randomly rotated *AFTER* the photons left the source...
DrChinese said:Try to come up with a set of data points for a Bell test in the Mermin format (I have that on one of my pages). So that is at 0, 120, 240 degrees. You will see that NO realistic theory - local or otherwise - can account for this. Just try to put together the dataset and you will quickly see none is possible. So that seems to rule out all hidden variable theories right there. Let's call this the MAIN RESULT: no hidden variable formulations are possible without outside help.
I do not see connection with your post #108 but yes this is my personal speculation that illustrates problems with your personal speculation about this overlapping effect.DevilsAvocado said:Well yes, but this is only your personal 'speculations', right? And I do think you got it somewhat wrong... check my https://www.physicsforums.com/showpost.php?p=2685669&postcount=108".
From wikipedia - http://en.wikipedia.org/wiki/Superposition_principle" states that, for all linear systems,The superposition of the particle (photon) is when it passes both slits simultaneously.
Particle = superposition
Wavefunction <> superposition
I do not make such assumption.DevilsAvocado said:You make the assumption that the pros making the experiments are 'fighting in the dark', to get some 'exiting results' to flash to the world... anything...
First, scientist do not to say things like "Hey! I can prove some weird stuff!" because they relay on http://en.wikipedia.org/wiki/Scientific_method" . They say things like "Results of experiment is in agreement with some weird hypothesis." This is because you can not prove theory with experiment but only disprove competing theories.DevilsAvocado said:I’m not in the 'business', but I do know that if a scientist says "Hey! I can prove some weird stuff!", he or she is going to be scrutinized by a lot of very smart people, trying to find any weakness in the claim.
Of course there are swindlers, who make every effort to fool the whole world, but they are rare, and they do not survive the fight against reality, in the long run.
You are not very careful with your statement.DevilsAvocado said:So, what have we got? Well, we have a theory that all agrees is mathematical correct and reliable. This theory makes a prediction:
Either X is true or, Y or Z must be violated.
X = Local Hidden Variables
Y = Counterfactual Definiteness (Heisenberg Uncertainty Principle)
Z = Locality
This is quite loose statement. There are things in QM that are not very strictly established like correspondence between certain things in mathematical formalism and physical reality. Because of that QM still can accommodate quite different interpretations.DevilsAvocado said:Now, we know from the theory that X is not true if we accept that QM is a correct theory (and we all agree that QM is the most precise theory we have). To reverse X to true, we have to abandon QM, and start from scratch.
DevilsAvocado said:Therefore, the most healthy choice between QM=true/X=false or QM=false/X=true, must naturally be QM=true/X=false.
Y (Heisenberg Uncertainty Principle) is a fundamental part of QM, which we have conclude true, then naturally Y must also be true!
All this is achieved by natural reasoning, common sense, and a very solid theory.
Now, when we start to perform Bell test experiments, every experiment indicates that Y or Z is violated!
What’s the most logical to do in this situation?? Well, it’s not start a "Denial Camp" to reintroduce X as true – it’s way too late for that!
We are getting the 'expected' results from the experimentalists, and it’s not sound to start questioning if the scientists making the experiments are 'retards' or 'swindlers'...
Come on!
Okay! Let’s start with not throwing the logic away in the evaluation of Bell test experiments!
DevilsAvocado said:This is important and I have to be sure.
Causal locality
If we set LHV to be +1 & -1 before sending the photons, we are not violating any locality. It’s just a matter of sending away 'predefined letter' in an 'envelope', and we know the outcome in advance, right...?
Constitutive locality
The receivers of the 'envelope' are physically separated in space-time, i.e. they have no connection FTL, right...?
DevilsAvocado said:Okay, can we 'refine' this and say – According to SEP the 'cause' of EPR is not "spooky action at a distance", it’s 'something else', but SEP can’t say anything about that. (right?)
DevilsAvocado said:>> This is extremely interesting! <<
Wow! I thought we only had one "problem" with the "spooky action at a distance", but this proves it’s much worse2!
Let’s see now... IF we assume there ARE "spooky action at a distance" AND the values of the Particles are 100% RANDOM, and the OTHER Particle must obtain the OPPOSITE value instantly. THIS CAN’T BE DONE DUE TO RoS??