Talk:Afshar experiment/Archive 14

Critiques is OR

Well, I'm giving up on this article, and can't waste any more time on it. The Critiques section is entirely OR as all of those papers predate my paper and have not addressed my experiment at all. Anyone not familiar with the facts of the case would be misled to think that the authors of the cited papers in the reference have indeed written those papers in response to my work. Michael, if you think this is the way to conduct science in Wikipedia, then I will have nothing to do with this sad joke. Goodbye. P.S. Thanks Linas and Looper for the effort. Dndn1011, sadly you are being unwittingly supportive of Michael's OR here, and hence lose credibility in the long run. Just a little heads up...-- Prof. Afshar 20:25, 17 November 2006 (UTC)

I was not aware of this. I assumed that the quoted critiques were responses. If they are not responses then they do not belong in the article. It is a shame you are giving up, however, when progress is clearly being made. The article is after all much less biased now, I feel. Dndn1011 23:15, 17 November 2006 (UTC)

The quotes are direct responses to Afshar's experiment. If not then I quite rightly should be banned from here. --Michael C. Price ^talk 23:22, 17 November 2006 (UTC)

It is also a shame that after much effort and work on my part to try and assist the creation of a more balanced article, Afshar should just dismiss me without thanks, and indeed incorrectly state my position. I actually agree that the Critiques section has been primarily OR and have been lobbying to have this changed. In fact I have strongly argued that there was bias and OR and actually made changes to the article on this basis. But we are trying to reach a concensus here and that can not be done without flexibility and appreciation of other views. But in the end, my motivations are merely for fairness and clarity, not for recognition or friendship or to advance my career or whatever else. Thus thanks are not necessary. Dndn1011 12:17, 18 November 2006 (UTC)

Claiming that "all of those papers predate my paper" are by definition OR is wrong. Analogy time: if I claimed I had a perpetual motion machine would it be OR to point to the 1st law of thermodynamics? --Michael C. Price ^talk 21:06, 17 November 2006 (UTC)

Your emotions have completely clouded your judgment my man. Your analogy is as flawed as all other logical inference you have made so far. The assumption in the above analogy gives the following equivalence: my experiment = perpetual machine. Well, in contrast to the perpetual machine, my experiment has been verified to work by Harvard faculty and other experts... Since you are fond of logical fallacies, "Have you stopped beating your wife?" P.S. please restore the link to my rebuttals, just in case some fair-minded individual wishes to dig deeper.--Prof. Afshar 21:14, 17 November 2006 (UTC)

Your assumption is quite incorrect and quite irrelevant to the point of the analogy, which is that dates of sources are irrelevant to the point being elucidated. --Michael C. Price ^talk 22:21, 17 November 2006 (UTC)

The relevance is that they do NOT talk about my experiment, and are NOT written to do so. You are putting out OR here and you know it.-- Prof. Afshar 22:55, 17 November 2006 (UTC)

Let's start from the top. Do you accept that "The Schrodinger wave equation is generally seen [by physicists] as in accordance with Bohr's philosophical views on the Complementarity Principle."? In other words would a physicist accept this as true? Yes or no? Note that this is a different question from "Is the Schrodinger wave equation in accordance with Bohr's philosophical views on the Complementarity Principle."? Although that is also a damn good question. --Michael C. Price ^talk 23:08, 17 November 2006 (UTC)

No Don't. This is about creating a fair article. Please read the notice at the start. Such discussions belong else where. Because wikipedia is supposed to be about reporting facts, areas of controversy should be merely noted as such, but not thrashed out here, this is not the place for it. Dndn1011 23:21, 17 November 2006 (UTC)

The first question posed (the one in the article) is not about physics, but about what physicists believe. I modelled it on the requirement for Wikipedia:Reliable sources, where they make an analogy with Earth's elliptical orbit. The 2nd question is about physics and, although interesting, is not actually relevant to writing the article, I agree. --Michael C. Price ^talk 23:31, 17 November 2006 (UTC)

Discuss

• The modern understanding of the role of quantum decoherence in the destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from the quantum to classical; in the decoherence view there is no classical-quantum divide, as enshrined by complementarity, and (again, in the decoherence view) any experiment claiming to violate complementarity needs to address the issue by carefully defining complementarity from a decoherence perspective.

Lets get this right before it goes in the main article. CL

First of all, does Complementarity "enshrine" a "classical-quantum" divide. Would it not be more correct to say a "wave/particle" divide. And before anyone puts it back in the main article lets cover all the points. This is but the first. CL

Now it depends on what Michael is trying to say. If complementarity is the object then the "wave/particle divide" correction seems right. But if the object of the sentence is "classical-quantum divide" then we need to remove the reference to complementarity. The two versions are:

A: Complimentarity = wave/particle divide (ie. not quantum/classical divide)

• The modern understanding of the role of quantum decoherence in the destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from the quantum to classical; in the decoherence view there is no wave-particle divide, as enshrined by complementarity, and (again, in the decoherence view) any experiment claiming to violate complementarity needs to address the issue by carefully defining complementarity from a decoherence perspective.

B: Decoherency = abolition of quantum/classical divide:

• The modern understanding of the role of quantum decoherence in the destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from the quantum to classical; in the decoherence view there is no classical-quantum divide, and (again, in the decoherence view) any experiment claiming to violate <?> needs to address the issue by carefully defining <?> from a decoherence perspective.

As can be seen, even when corrected, the passage still doesn't go anywhere. It needs some serious attention. CL.

All that's left readable (for the moment) is:

• The modern understanding of the role of quantum decoherence in the destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from the quantum to classical; in the decoherence view there is no classical-quantum divide. See Decoherence and the transition from quantum to classical, Physics Today, 44, pp 36-44 (1991); and an updated version from 2003:[1]</ref>

But this is not (yet) a criticism. CL

Where did the statement in question already come from? Has the statement as a whole been cited? Or is it inferred from other sources? If it is inference, then it is an danger of being OR. Dndn1011 09:23, 18 November 2006 (UTC)

Please read through the recent history of this debate. An answer of sorts is there to be found. There are no OR issues at the moment - as the passage is currently undergoing discussion here. CL.

Original research in critiques section

I can't tell who is editing what in which way any more. Somehow, the critiques section was just now exactly backwards. I restored the list of major critics and thier criticisms, and removed the home-grown wiffle-waffle mis-interpretations of quantum mechanics.

Just to be clear: the major critics are experts in quantum mechanics, and have the credentials and track record to write about such things. A list of who they are, and a pointer to thier critiques is appropriate. A one-or-two sentance summary of each author's points would also be appropriate.

What is not appropriate are the attempts to distill all of quantum mechanics into a few paragraphs of "general criticisms". All of the attempts to do this so far have been severely flawed. I am now convinced that it is not possible to summarize in this way, at this time. linas 01:25, 18 November 2006 (UTC)

Those flaws you mentioned have been corrected. If you are removing on grounds of OR then please be precise and tell which claims are OR. Let's start with the first two points:

• The Schrodinger wave equation is generally seen as in accordance with Bohr's philosophical views on the Complementarity Principle. In this view since the former is obeyed in Afshar's experiment the latter can't be violated.

No man is an island and time waits for now man. Ergo, time waits for no island. This is not just original research, it is utter nonsense masquerading as some sort of statement pretending to have meaning. Micheal, this is bullshit, and you know it. Stop it.

Unsigned but, to judge by the profanity, I guess it is Linas. Please address your comments to the version in the article, which has been reworded and resourced. --Michael C. Price ^talk 18:48, 18 November 2006 (UTC)

• Complementarity is often viewed as being enforced by the uncertainty principle. In this view since the latter is obeyed in Afshar's experiment the former can't be violated.

Cars are often viewed as being stopped by brakes[1][2][3][4][5]. In this view since the car stopped, the brakes must have been applied. I think you are so emotionally involved in this issue that you can no longer think straight. You may want to think about taking a wiki-vacation, and cooling off for a while. linas 16:34, 18 November 2006 (UTC)

The structure is HUP => Cmpl and Afs => HUP therefore Afs => Cmpl. Now what was that you were saying about thinking straight? --Michael C. Price ^talk 18:48, 18 November 2006 (UTC)

The first point is the two sentence summary you asked for, and referenced, of the authors that you regard as credible. Which precise steps do you regard as OR? --Michael C. Price ^talk 02:18, 18 November 2006 (UTC)

I think it better to have a brief overview with references so the reader can do their own further research. I do not believe it is good form to have in the main body of the article a list of people who disagree with Afshar. It is fine to state the general issues and then have references to these people in the footnotes, as long as there are not too many. Too many and a sense of bias will be created. The OR issue is that if the article appears to contain significant work in collating together the opinions of others, it will become indistinguishable from a research paper. I know it is a fine point, because in a sense any work on a article requires collation of information. I guess it is a case of the motivation and extent. Listing the major issues and giving references for these is one thing (and quite acceptable), however collating together many sources with the intention of disproving a point of view is clearly OR. The article had been leaning very heavily towards the latter, but now is much improved, although I prefered the critiques section when it did not list dissenters by name. If the remaining critiques have been found not watertight, then they should be removed. The article should contain that which is undeniable and mention areas that have yet to be resolved. Actually weighing those issues in the balance is not what the article is for, as this is an encyclopaedic entry not a research paper. Dndn1011 09:21, 18 November 2006 (UTC)

Please do not remove the list of criticisms that linas restored. They are significant criticisms by various independant scientists and Afshar has provided equally significant rebuttals. Both the criticisms and rebuttals provide an important set of links for researchers who wish to look into the experiment more deeply. CARL LOOPER.

I agree that they should all remain in the article. BTW, Carl, you really should create a login account with Wikiepdia - it would make life easier for both you and us. --Michael C. Price ^talk 10:50, 18 November 2006 (UTC)

Fair enough.--Carl A Looper 12:13, 18 November 2006 (UTC)

Bohr describes the mathematical formalism (e.g. the Schrodinger equation) as "an adequate tool for a complementary way of description". so the issue is settled. (N.Bohr, "Discussion with Einstein on Epistemological Problems in Atomic Physics", in Albert Einstein: Philosopher-Scientist, P Schilpp ed (Open Court, La Salle, IL, 1949). [2]--Michael C. Price ^talk 09:47, 18 November 2006 (UTC)

Please discuss

"Complementarity is often viewed as being enforced by the uncertainty principle. In this view since the uncertainty principle is obeyed in Afshar's experiment the complementarity principle can't be violated by it." - Michael Price

It is said here that complementarity is often viewed as being enforced by the uncertainty principle. Yet the reference is about something altogether different

And I quote:

"Demonstrates that complementarity is enforced, and quantum interference effects destroyed, by decoherence (irreversible object-apparatus correlations induced by the detector), not by Heisenberg's uncertainty principle itself."

ie. the reference is about the uncertainty principle not enforcing complementarity.

But if the uncertainty principle does not enforce complementarity then how does it follow, that in Afshar's experiment (or any other experiment), it would decide to change it's mind and enforce complementarity?

I mean I'm open to suggestions.

--Carl A Looper 14:15, 18 November 2006 (UTC)

'Complementarity is often viewed as being enforced... etc' : I have never liked this statement. It is weak. The references pre-date the experiment. This appears to be Mr. Prices opinion with non-supporting references. also the footnote says "Demonstrates that complementarity is enforced, and quantum interference effects destroyed, by decoherence (irreversible object-apparatus correlations induced by the detector), not by Heisenberg's uncertainty principle itself.". This is at odds with the assertion "Complementarity is often viewed as being enforced by the uncertainty principle". SO overall it makes no sense. Dndn1011 14:48, 18 November 2006 (UTC)

The statement means exactly what it says. Granted it looks confusing unless you actually read the source. I've expanded the inline summary to make it slightly clearer:

Wrong. The statement means exactly what it says and is not confusing - until you read the "source". In which case you should remove the "source" as it is not the source of the statement. At which point your statement becomes unsourced. And ergo "OR". --Carl A Looper 21:07, 18 November 2006 (UTC)

• Complementarity is often still viewed as being enforced by the uncertainty principle. In this view since the uncertainty principle is obeyed in Afshar's experiment the complementarity principle can't be violated by it.

Where the inline text now reads:"Demonstrates that complementarity is enforced, and quantum interference effects destroyed, by decoherence (irreversible object-apparatus correlations induced by the detector), and not, as is popularly believed, by Heisenberg's uncertainty principle itself." Clearer? --Michael C. Price ^talk 16:05, 18 November 2006 (UTC)

No. All that has happened now is that you appear to be presenting OR on the subject of how popular opinion is wrong. As the papers you refer to are over 10 years old, it raises the question of why so many other have not shared the insight you are appear to be raising. For this footnote to stand it would itself require a citation, which I have added. Dndn1011 17:17, 18 November 2006 (UTC)

I hope it is now clear that it isn't OR. --Michael C. Price ^talk 21:51, 18 November 2006 (UTC)

I would like to know how obeying the uncertainty principle means that complementarity can not be violated. Is not in principle possible to have something act as both a wave and a particle at the same time and yet also be adhering to the uncertainty princple? More pertinently, do the current theories being put forward as objections against Afshar's view actually explain the experiment's findings? If not, then all bets are off... any supporting theories of a counter argument could have a flaw in some way. Dndn1011 15:03, 18 November 2006 (UTC)

As pure wave and pure particle, at the same time? No that is not possible. The trade off is expressed in the uncertainty relation. To answer your 2nd point, see the explanations offered by the critics that appears in the reference section of the article. They are saying that there is nothing to explain. --Michael C. Price ^talk 16:05, 18 November 2006 (UTC)

Just as a side point... how does refraction work? How can a particle be refracted when refractive effects require the observed slowing down of light in a denser medium? As a wave this is easy to explain. But what happens to the particle? As it crosses the boundary does half of the photon travel at a different speed than the other? That seems unrealstic. Dndn1011 17:02, 18 November 2006 (UTC)

It is a side point, but interesting: the different expected behaviours for particles and waves was the main reason for the adoption of Young's wave model of light over Newton's particle or corpuscular view. It took Einstein and the quantum revolution to marry the two together. --Michael C. Price ^talk 18:34, 18 November 2006 (UTC)

Yes I know the story of all that. But that has not answered my question.Dndn1011 21:32, 18 November 2006 (UTC)

The photon has no size (until you get to string theory) so it is never half across anything. --Michael C. Price ^talk 21:51, 18 November 2006 (UTC)

• Dear Michael, you are wrong about the HUP and W-P duality. This is a major misconception suffered by a lot of non-specialist in the field. HUP has nothing to say about wave or particle aspects of a quantum system. It simply establishes the relationship between non-commuting observables such as position and momentum, or energy and time. For instance would you say that position is a purely particle property and momentum a purely wave property? Such assertions are absolutely false, and no expert uses it as such. On the other hand Complementarity covers what can be called purely particle aspect (which-way information, K) and purely wave aspect (the interference visibility, V). These two properties do not have a similar relationship as say momentum and position in HUP. That is why Complementarity was proposed by Bohr, otherwise he would have just used HUP. He made it perfectly clear that his Complementarity Principle was more fundamental and more importantly a distinct physical principle than HP. This is an extremely crucial fact, without which all following assertions are just as flawed. Please let me know if you have any questions in this regard.-- Prof. Afshar 16:38, 18 November 2006 (UTC)

Afshar: This is from Complementarity (physics): "On the basis of Bohr's principle of complementarity, it is indeed universally accepted that the observation of two complementary properties, such as position and momentum, requires mutually exclusive experimental measurements.". This appears to be tying HUP with Complementarity. I would be grateful if you could clarify whether the article is incorrect, so that it can be edited. I believe the "universally accept" part is correct, but not that this is accepted on the basis of Bohr's principle of complementarity, but in fact on the basis of HUP. Dndn1011 17:30, 18 November 2006 (UTC)

Dndn1011, the relationship between position and momentum are governed by the HUP inequality, whereas V and K of Complementarity in which-way experiments have a different relationship: V^2+K^2<=1. Although often the term "complementary" observables are attributed to momentum-position and V-K, they mean different things. Still waiting for Michael to comment.-- Prof. Afshar 17:45, 18 November 2006 (UTC)

Understood, so you are saying there are two "principles of complementarity"? One is for HUP and the other for C (complementarity)? And both principles are attributed to Bohr? Sorry I need to be sure about this to see if the other article needs work or not. Thanks. Dndn1011 17:50, 18 November 2006 (UTC)

No, there is a single principle of complementarity, which is manifested in different ways in different experiments. The V-K relationship only applies to "welcher-weg" (Which-way) experiments. My experiment only addresses PC in which-way experiments. P.S. I just saw your edit to critiques: "Complementarity is often still viewed as being enforced by the uncertainty principle[8]." That is actually incorrect. It is now understood that Complementarity is NOT always enforeced by HUP thus a different physical concept. The very Ref. to Scully et al. paper suggested and experiemtn to test this fact, and it was carried out by Rempe et al, which positively proved it.-- Prof. Afshar 17:55, 18 November 2006 (UTC)

OK, got it thanks. Although it is easy to see how this can be confusing. The other article does however mention that Bohr stressed the important of the difference between Complementarity and HUP. For the benefit of readers this should probably be clarified generally (not just in this particulat article), although I am not qualified to do this.

As for my edit, I merely added a {{Fact}} tag on Mr. Price's contribution. Dndn1011 18:01, 18 November 2006 (UTC)

I see Afshar is still looping round previous discussions; nothing I can do about that, I guess. As for the {{Fact}} tag, Dndn1011, it is rather superfluous since the article cited is the source of of the claim that HUP is often (and incorrectly) viewed as enforcing complementarity (see the opening paragraph of the SciAm ref where they say "Since the idea of complementarity was first enunciated 70 years ago, a belief common amongst many physicists has been that it is simply a consequence of the uncertainty relation."). But I am pleased to see that debatable sources are now being tagged instead of some idiot doing a hit-n-run delete. Perhaps we can start making progress again. If no one objects I'll remove the citation req tag? --Michael C. Price ^talk 18:29, 18 November 2006 (UTC)

Actually the tag is for the "popularly believed". It appears to make a statement about what is popularly believed at the moment. The current edit is even more confusing. Dndn1011 21:10, 18 November 2006 (UTC)

Michael, since you agree that "HUP is often (and incorrectly) viewed as enforcing complementarity", I would appreciate if you add the caveat "incorrectly" into the sentence in the article. You will see that as soon as you do that, the nature of the sentence as a critiques vanishes, since it makes the statement irrelevant to my experiment. This is good test of your fairness.--Prof. Afshar 18:38, 18 November 2006 (UTC)

Done. Tagged it in the 2nd sentence to avoid grammatical confusion. --Michael C. Price ^talk 19:00, 18 November 2006 (UTC)

Come on man! "Outdated" is not the same as "icorrect", and its use in the sentence is misleading. Why do I have to squeeze fairness out of you? Stick to your own word Michael.-- Prof. Afshar 19:25, 18 November 2006 (UTC)

"Incorrect" in the decoherence view. Since I am accused of pushing the decoherence POV I thought I'd soft pedal this. "Arguably outdated" seemed a reasonable comprimise. I'll think about, but anyone else can change it in the meantime, of course. --Michael C. Price ^talk 19:36, 18 November 2006 (UTC)

Anyone including Prof. Afhsar of course :) Dndn1011 21:04, 18 November 2006 (UTC)

I agree with Prof Afshar. "Outdated" is an altogether different concept from "incorrect". Wearing a top hat is outdated. Wearing a goose is just incorrect. --Carl A Looper 21:50, 18 November 2006 (UTC)

• Michael, so you'll "think about it"? I gave you a chance, and you blew it; we're done. The entire sentence should be removed from the critiques section because regardless of it being outdated, incorrect or invalidated, it is not a critique of the experiment. The mere mention of it makes the reader confused as to its relation to the experiment. If Michael won't do it, please other editors do take the action. I WILL NOT TOUCHT THE ARTICLE MYSELF. As for the Schrodinger equation being obeyed in the experiment, I will discuss it (or anything else) only after this sentence has been removed from the article.-- Prof. Afshar 22:24, 18 November 2006 (UTC)

I've removed the HUP=>C "critique" on the basis of the above discussion. --Carl A Looper 23:03, 18 November 2006 (UTC)

Thank goodness for that. Time for an archive of this talk? Dndn1011 23:07, 18 November 2006 (UTC)

Yes, a wonderful improvement: now people who think that the complementarity is enforced by the HUP -- which includes most physicists BTW, because that is what the textbooks still say -- will think that Afshar's experiment can't violate complementarity because the HUP is maintained. Ah well, have it your own way. --Michael C. Price ^talk 23:40, 18 November 2006 (UTC)

Physicists don't get their information from text books. They determine what is written in them. Reading is a critical activity. To see if what is written can't be elaborated upon. --Carl A Looper 00:20, 19 November 2006 (UTC)

A lovely bit of rationalisation for the deficiencies of the article -- but I don't really care (if I did I'd have restored the lost text). Ever heard of a physics reading list? --Michael C. Price ^talk 00:33, 19 November 2006 (UTC)

A HUP=>C critique of the experiment was implied by the passage in question. But no such critique was forthcoming. The passage did not go anywhere. If the purpose of the passage was to reference a critique of HUP=>C it did a decidedly awkward job at that. And as discussed, if that was the intention of the passage, then it did not constitute a criticism of the experiment - ergo it just deleted itself. --Carl A Looper 00:49, 19 November 2006 (UTC)

If you did care you would not restore the text. Ergo. You do care. You are now a physicist. --Carl A Looper 00:57, 19 November 2006 (UTC)

The Bohr argument

Niels Bohr stated that "an adequate tool for a complementary way of description is offered precisely by the quantum-mechanical formalism" [4] In this view, since the formalism (e.g. the Schrödinger equation) is obeyed by the photons in Afshar's experiment, Bohr's complementarity principle can't be violated by the experiment.[5][6][7] - Michael Price

This is sort of like like saying:

Since complementarity is correct, Afshar's experiment can't violate it.

Or:

Since Afshar's experiment demonstrates that complementarity can be violated, Bohr can't be correct.

Don't you think? But the references are good. Just not sure if you've characterised them with very well. Perhaps it is better to let the critiques speak for themselves.

--Carl A Looper 02:11, 19 November 2006 (UTC)

Your two paraphrases are completely wrong. --Michael C. Price ^talk 08:51, 19 November 2006 (UTC)

Yes they are. And the reason why is because they are assembled without any regard for what they might otherwise signify. --Carl A Looper 10:20, 19 November 2006 (UTC)

Which is all rather irrelevant since your two "paraphrases" are not equivalent to the first statement: i.e. they are not paraphrases. This is sort of like like saying: "Black is white." Don't you think? --Michael C. Price ^talk 10:35, 19 November 2006 (UTC)

That's right. The issue is not that black and white. And I may be unfairly characterising the original passage that way, so let us agree on that and turn to what the passage might signify. The ball is now in your court. --61.95.31.212 23:17, 19 November 2006 (UTC)

You forgot to logon? (You can set your account to "remember" your login between sessions. Saves effort.) Bohr seems to be saying that the formalism (i.e. solutions to QM equations) will always yield a higher-level complementary description (=interpretation?), i.e. that the formalism can never produce a solution that doesn't permit a higher-level complementary description. Presumably this is restricted to formalisms that were known in 1949, but that would include the Schrodinger equation, which is adequate for our purposes. How do you read it? --Michael C. Price ^talk 01:20, 20 November 2006 (UTC)

Yes, I noticed the logon error. Re. the passage. I can't read it very well. The quote, for example, is unsourced, so I can't track down the context to explore what it might otherwise mean. And the second sentence ("in this view...") relys on the first sentence. And the references for the second sentence (the critques), which I assume support the first sentence, I read rather differently - if only by virtue of the fact that I can't actually read the first sentence. I'll address your elaboration soon. I'm in the middle of other concerns. But we have made a start. --Carl A Looper 01:31, 20 November 2006 (UTC)

Just added this to the reference text. Provides much more context. --Michael C. Price ^talk 01:39, 20 November 2006 (UTC)

Thanks Michael - very much appreciated. I have some other concerns but let me read your reference first and we'll address those later (if they are stiil relevant). --Carl A Looper 01:56, 20 November 2006 (UTC)

Have read the reference now. Now please forgive me if this sounds strange but I'm just trying a reading of the sentence: Since the photons in the experiment (ie. the observables) obey the formalism (ie. are predicted by the formalism) then (since the formalism is a good tool) ... <something needs to go here> ... Bohr's complementarity principle can't be violated by the experiment.

My main problem is that the referenced critiques are not really signified by whatever you've written in the passage. And if not then what is the purpose of the passage? Perhaps we should look at the critiques. --Carl A Looper

Replace "<something needs to go here>" with "and, since Bohr regarded complementary as a consequence of the formalism (which the experiment conforms to), then...". Does this clarify why the quotes from Motl, Unruh etc support this view? I think they do. --Michael C. Price ^talk 10:07, 20 November 2006 (UTC)

No, because it's not clear if Motl et al, support that reasoning. Or Bohr for that matter. The Principle of Complementarity is positioned by Bohr as something more fundamental than the formalism. The formalism is an "adequate tool". That is, the formalism is compatible with the principle. The principle is not a consequence of the formalism. Or at least that is the way Bohr frames it. --Carl A Looper 10:30, 20 November 2006 (UTC)

You seem to be bulding a lot on the word "adequate" and ignoring the word "precisely". Suppose that he had said "inadequate" instead, then you would be correct; but he didn't, he said the reverse. Sorry, I the way it read it is that Bohr intended the principle to be a consequence of the formalism. And that is how every physicist I know understands it, and how Motl et al understand it. That's why they are taught together in text books and at universities. This is a mainstream view, whether you or Afshar agree with it is another matter. (This is despite the debate over whether complementarity is enforced by the HUP or decoherence, because the latter two are both aspects of the formalism.)--Michael C. Price ^talk 10:51, 20 November 2006 (UTC)

This is not a game of logic. The words "adequate tool" are in index to the reference you have provided. The history behind the principle of complementarity is discussed there. If you are not interested in that history then why reference it. If it's just the formalism you are interested in - the tool - why do you even bother trying to reference such material. Why don't you quote from your text book instead. --Carl A Looper 12:13, 20 November 2006 (UTC)

It is all about logic. Whether you call that a "game" is your business. If I'd quoted from a text book no doubt Afshar and others would protest that that's not what "Bohr meant"; so I have quoted Bohr instead. --Michael C. Price ^talk 14:08, 20 November 2006 (UTC)

I've put together some quotes from each critique that might help to formulate a breif of such although these are just ones that interest me:

"The presence of the interference pattern in Afshar’s experiment is only inferred, but according to the orthodox interpretation of quantum mechanics it has to be measured in order to be described by the quantum mechanical operator formalism. This requirement is well captured by Wheeler’s famous dictum to the effect “that only a registered event is a real event” [23]." - Ole Steuernage

"The more you can infer about "which way" the less you know about the interference." - Bill Unruh

"I can't guarantee that everything Bohr has ever said about complementarity was true; it's just my understanding of the complementarity principle that has not been violated by this experiment, and Shahriar may have found a statement due to Bohr in the libraries or archives that was proven incorrect by this experiment. (Thanks to Bert Halperin for discussions about this point.)" - Luboš Motl

The Motl and Steuernage critiques exhibit a similar argument. The complementary (mutually exclusive) observables are only those observables that have been emperically measured (as distinct from inferred). And this is their understanding of the principle of complementarity - otherwise referred to as "Bohr's". Since this is not violated, the principle of complementarity is not violated by the experiment.

But Unrah's language differs somewhat. In Unrah's language the principle of complementarity would appear to equally apply to inferred 'observables' - the otherwise invisible waves (or interference) on the one hand, or "which way" on the other.

And if we were to include Georgiev's contribution we might have yet another argument.

I'm eager to read Danko's argument, Michael, so if you'll excuse me from this interlude, I'm going to put my critical goggles on and have a good read of that. In the meantime, let me know what you think of what I've said. And consider the linas argument as well - that perhaps it is unwise to burden a few sentences with so much responsibility.

Some questions to help (in reading the critiques)

Is our modern definition of complementarity based strictly on observables?

Did Bohr really require complementarity be defined strictly in terms of observables (to the exclusion of inferences) in which case what does Unrah (or Bohr) mean by infering "which way"?

What is it about Afshar's experiment that requires complementarity be defined emperically? But not necessarily, it would seem, in Unrah's case.

What is the difference between an experiment designed to demonstrate complementarity and one designed to violate it? Does it require changes to the epistomological conditions/conclusions you can make? And why?

• In Danko's argument the axiomatic definition of V is not the same thing as an emperical 'definition' of V as it might have otherwise been thought. Which is almost a relief. The terms "a priori" and "a posterio", acquire new significance. The formalism allows one to express the principle of complimentarity such that Bohr's interpretational crutch "there is no quantum world", is not just unnecessary but possibly incorrect. The principle imposes a limit on the inferential meaning of the observable. The observables become "entangled" so to speak. One can not math consistently say A and B. One must say A or B. ie. in spite of the observables, not because of such. And the argument for mathematical consistency is an extremely powerful one. --Carl A Looper 19:49, 21 November 2006 (UTC)