Talk:Afshar experiment/Archive 9

Tone it down; equations
Please tone it down. This borders on a religious or metaphysical argument. The biggest problem with the Afshar experiment appears to be that it doesn't invalidate any specific mathematical formula; rather, it all hinges on the interpretations of some arguably vague pronouncements by Bohr, Heisenberg and others. As such, the debate is likely to remain unresolvable.

As far as I can tell, Afshar's experiment is in complete agreement with the mathematics of QM. It is possibly that Afshar's experiment may be able to shed light on decoherence, and may even be able to distinguish between rival theories of decoherence. I don't know. However, since decoherence seems to be the currently most popular, most accepted route to understanding "wave function collapse", I strongly suggest that both sides search for a way of reformulating this experiment in terms of the language of decoherence. That way, there might be some actual forward progress. linas 15:35, 7 July 2006 (UTC)
 * I agree that the interpretation of Afshar's experiment "hinges on the interpretations of some arguably vague pronouncements by Bohr, Heisenberg and others." and that is probably unresolvable. But the issue of updating of the critique section only depends on the interpretation of what the mainstream regards as the scope of decoherence -- and that is resolvable, since a cursory examination of the reference titles (e.g. "Decoherence and the transition from quantum to classical") shows that they believe the scope of decoherences covers the whole of Copenhagenism (which would include Complementarity in all its various guises).  --Michael C. Price talk 15:54, 7 July 2006 (UTC)


 * Dear Linas, thanks for stepping in! My experiment was actually aimed at a particular relationship (V^2 + k^2 <=1) universally accepted by experts in the field as the embodiment of Complementarity. It was derived over the past few decades by various investigators From Wooters and Zurek to Greenber-Yasin, Shimony-Jeager, Englert-Scully-Walther, and tested by numerous experiments. This relationship is proven to be independent of Heisnberg's Uncertainty Principle, and is the de facto definition of Interferometric Duality in Weclher-Weg experiments. It has been clearly violated in my experiment.
 * Now as to whether decoherence has anything to do with the experiment, I strongly suspect it does, and have designed new experiments that "catch" the photon in the act. But to be chronologically honest, I can only defend using the original line of reasoning: The duality relation predicts X, this experiment shows Y with a very high statistical significance. I have never claimed the experiment violates QM, and have indeed used QM formalism to derive expected calibration data, and proved other important boundary condition concerns. I cannot speculate on what decoherence has to do with results here without further experimentation, and anybody who does, should use a reliable reference for his/her thesis, and not generate OR on Wiki. All I am asking is to be objective and stick to what is accepted basis for the background of the problem. I have many new insights I'd like to share, but will only reflect in Wikipedia after they get published. I suggest the same to all editors, both pro and con. Best regards. -- Prof. Afshar 16:09, 7 July 2006 (UTC)


 * Its possible that I failed to pay sufficient attention in the past, but I did not realize that (V^2 + k^2 <=1) is being attacked. I don't remember seeing this in the pre-prints. I strongly suggest leveraging this as the theoretical development of the concept. I'll reiterate for now: unless the experiment somehow attacks some concrete mthematical formulation, it will continue to devlolve into vile philosophical debate.


 * I think Drezet wrote up breif theoretical review of (V^2 + k^2 <=1) Englert-Greenberger duality relation, which I think I cut-n-pasted into the article on complementarity (physics); we should thank Drezet again for that. I'd be interested in an expanded presentation of Englert-Greenberger duality relation, and then the interpretation of this experiment in that language. linas 22:23, 7 July 2006 (UTC)

Conflict, arbitration

 * Afshar, this is not the place to discuss future experiments or debate various aspects of QM. I humbly remind you that this is an encyclopedia, and this page is for discussing the article at hand. Please respect Wikipedia and discontinue your inappropriate behavior. (unsigned anon??)

Since Afshar does not address the issues raised here on the talk page and shows a poor grasp of Wiki standards (especially OR) I have gone ahead and updated the Critiques section. --Michael C. Price talk 18:04, 7 July 2006 (UTC)

Dear Michael, as I said before, since you have taken it upon yourself to deliberately incorporate errors into the article without proper references cited, I am initiating an arbitration by an admin, probably Gareth Hughes. Please refrain from editing the article until the arbitration has ended. Regards. -- Prof. Afshar 19:43, 7 July 2006 (UTC)
 * I have not deliberately introduced errors -- that you persist in accusations of bad faith is contrary to Wiki policy and will count against you. --Michael C. Price talk 19:49, 7 July 2006 (UTC)
 * Dear Michael, please let the admins judge the situation. Thank you for your patience!-- Prof. Afshar 19:56, 7 July 2006 (UTC)


 * Afshar, you obviously dont "get it" when it comes to Wikipedia. You call for third party dispute resolution, and then immediately roll back the questioned article text. This is childish behavior. Please respect Wikipedia and refrain your self from lording over the article. —The preceding unsigned comment was added by 168.150.251.39 (talk • contribs) 21:00, 7 July 2006.


 * Getting it also involves signing posts and not attacking other users. — Gareth Hughes 20:04, 7 July 2006 (UTC)


 * @anon: There is also a problem with anti-troll-trolls, those contributors overdoing things when trying to defend Wikipedia. Our most prominent one, User:Wik, is serving a rather long ban for this.
 * @Afshar: Please be aware of some of your misunderstanding of Wikipedia's workings:
 * Admins don't resolve content disputes
 * Arbitration can only be initiated by posting a request on WP:RFAr, not to individual admins. Arbitration requests without prior steps in Conflict resolution tried, are usually rejected.
 * For an intersting precednet in arbitration, please have a look at:
 * Requests for arbitration/Carl Hewitt
 * Pjacobi 20:22, 7 July 2006 (UTC)

Thanks, an illuminating set of links. I shall restore my reverted text on the grounds that: --Michael C. Price talk 21:56, 7 July 2006 (UTC)
 * It links to better referenced articles than the Afshar experiment itself is, which by contrast has no peer-reviewed references.
 * As has been repeatedly demonstrated the contents of the Afshar experiment article are the views of Afshar and very few (any?) others. There is a need for balance in the article; presenting the mainstream position on decoherence superseding Bohr's complementarity would help address this lack of balance.
 * It is contrary to Wiki policy for Afshar to contribute to his own experiment's article (see Pjacobi's posted link "Editors should avoid contributing to articles about themselves or subjects in which they are personally involved, as it is difficult to maintain NPOV while doing so."). That Afshar should be reverting the balancing contributions of others is especially bad violation of this policy.

Please note that, on review of the edit history of this article, there have been a large number of hostile edits over the last several years, many from cranks and would-be debunkers with no knowledge of physics, and others from the educated but skeptical crowd. I am not aware of anyone actively defending this article from hostile edits other than prof. Afshar himself, and so I am tempted to give him some leeway in editing. His work and reputation are now tied to this; this includes conditions of employment, grants and funding, etc. and so there is a need to maintain decorum. linas 22:51, 7 July 2006 (UTC)


 * That's the reason, I'd like such articles to be deleted, until the dust settles. But with two failed AfDs, that doesn't seems to be an option. Your caveats are in line with the WP:LIVING, where extra courtesy is requested for subjects of a biography, who try to correct (or "correct") their articles. But this article is not a biography and if I didn't miss something it contains no ad hominem attacks against Afshar. Perhaps we can settle for, much, much shorter version? --Pjacobi 23:11, 7 July 2006 (UTC)


 * I'm actually happy with the article in its current state (well, don't hold me to that, I'd have to re-read it more carefully, but generally its more or less in good shape). It describes the experiment accurately, it alludes to the theory, states that its controvresial, and points to the critics who have criticized it. I don't see that shortening it would lessen the attacks. Indeed, a shorter article attracts more cranks: being less definite allows more room to posture and maneuver. I recall Danko's failed attempts to "explain" which disappeared once Drezet actually gave a valid presentation. Concreteness aids clarity, excessive brevity does not. linas 00:26, 8 July 2006 (UTC)

removed critique
I am removing the following text from the article:


 * Some common, popular views are:


 * Bohr's philosophical Complementarity Principle is identified with wave-particle duality which, in turn, is quantified by Heisenberg's Uncertainty Principle. Since the Uncertainty Principle is not violated by the experiment then neither is Complementarity.


 * the modern understanding of quantum decoherence and its destruction of quantum interference relegates Complementarity to the status of an epiphenomenon and hence irrelevant to understanding the foundations of quantum theory.

My reason for removing these is that (1) there is no evidence that these are "popular", and (2) they are overly facile, shallow critiques. They're what one would say if you didn't bother to think much about it. By contrast, Lumidek's critique is considerably longer and more detailed, and cannot be boiled down to the above setances, ditto for Unruh's. (FWIW, my personal favorite critique, which is that "no wave function collapse occurred, so nothing is proved", doesn't fit into that mold either.) linas 23:09, 7 July 2006 (UTC)


 * For evidence of decoherence's popularity you need only look at the number of published articles written on the subject. The motivation of decoherence is to provide a mechanism for understanding wavefunction collapse and the quantum-classical divide; once this is established there is no need of an a priori invocation of complementarity.  I fail to see how this is a shallow or facile critique, since the page on decoherence explains this in detail.  I find it strange that you are so quick to delete a decoherence-based critique since you are also suggesting that the article be written from a decoherence POV. --Michael C. Price talk 23:31, 7 July 2006 (UTC)


 * You thoroughly misunderstand me. I did not say "decoherence is unpopular". I said "there is no evidence that a decoherence-based critique of Afshar's experiment is popular".
 * So if I remove the word "popular" you'd be happy with it? --Michael C. Price talk 00:35, 8 July 2006 (UTC)


 * No because its not an adequate summary of the critiques. linas 15:59, 8 July 2006 (UTC)


 * Furthermore, I did not suggest that the article be re-written from a decoherence point of view. I was suggesting that prof. Afshar take up a serious study of decoherence, and see if he could frame his experiment in those terms.
 * A good idea but that's not what you said:
 * I strongly suggest that both sides search for a way of reformulating this experiment in terms of the language of decoherence.
 * which is open to more interpretation than you've indicated. --Michael C. Price talk 00:35, 8 July 2006 (UTC)
 * I am sorry, I had choosen my words poorly. It is what I'd meant. linas 15:54, 8 July 2006 (UTC)


 * The article space of WP would not be the appropriate forum for Afshar to publish his work on decoherence. Finally, what I wish to say is that the WP article space is not the right place for amateur attempts at debunking his ideas. If you think you have a coherent debunking of Afshar based on decoherence, then please do write it up as a paper, post it on your website, put it on Arxiv, etc. Then add a reference to it here. Do not, however, add a four-sentance hand-waving debunking to this article and present it as "obvious truth". linas 00:15, 8 July 2006 (UTC)
 * I did not present it as an "obvious truth", but I do think it is coherent and supported by the literature. And since Afshar's views are OR they need balance. --Michael C. Price talk 00:35, 8 July 2006 (UTC)


 * The text presents itself as an adequate summary of the situation, when in fact it is not. "The literature" consists of the four critiques. I may be mistaken, but I do not believe that any of the critiques mention decoherence, and I do not believe they try to reduce complementarity to an "epiphenomenon". As to "original research": prof Afshar is a (tenured?) physics professor at a university; a postition where unoriginal research is a lower priority. For better or worse, his experiment appeared as the cover story for the widely read New Scientist magazine, which makes it notable by WP standards. By contrast, your addition appears to be unpublished OR by you. I don't believe you have accreditation in physics; I don't believe you have written up this critique anywhere except at WP. OR by you does not balance out a notable, publicized experiment which you are mistakenly calling OR. linas 15:54, 8 July 2006 (UTC)


 * For the reasons stated above I am restoring the text lost by Linas's hit-n-run delete, with some modifications to make it more coherent and accessible. The first point has been recast in a form which has appeared before in the archived talk page. The second point has been re-worded for clarity.  If anyone still finds it too "overly facile, shallow" I suggest they follow Wiki practice of "improving not deleting".  All controversial articles need inline balance and not just a set of external links -- this is following the format of many other articles.  --Michael C. Price talk 07:51, 8 July 2006 (UTC)


 * I'm reverting on the grounds that your addition is pure, unsubstantiated OR. "Improving not deleting" will not change the status from OR to something else. The text yo wish to add does not improve the balance of the article. If you wish to critique the experiment, write up your critique in an essay, and get it published somewhere. Do not try to shoe-horn it into WP. linas 15:54, 8 July 2006 (UTC)
 * So Afshar can add his OR and POV to the article, but when I try to add some referenced balance it gets reverted? I think at the very least you owe us an explanation of why you regard it as OR -- as I've said the decoherence tack is mainstream, which bit of the argument do you not agree with?  There are plenty of refs at decoherence.  --Michael C. Price talk 16:01, 8 July 2006 (UTC)
 * I'll rephrase my request, since our views are not relevant: which part of the decoherence statement do you think is not supported by the literature? The entire point of the decoherence paradigm is to provide an explanatory mechanism for wavefunction collapse and the quantum->classical transition: do you accept this, or not? --Michael C. Price talk 16:15, 8 July 2006 (UTC)


 * Michael, I recommend that you just give up. Even if you make peace with Linas, Afshar himself will never stop fighting you. Look at his user contributions. And look in particular at this one, especially the false signature at the end. Afshar is not interested in contributing usefully to Wikipedia. His only interest is in enshrining himself, through this article, as the person who overthrew the principle of complementarity. He's willing to devote unlimited amounts of time to this, and he will wear you down until you give in.
 * I see someone is quite keen to delete the above paragraph. I wonder who that can be?  :-)  Their actions only serve to draw attention the text.  --Michael C. Price talk 17:49, 9 July 2006 (UTC)
 * The article is a loss. Just write it off and spend your time making contributions where they'll matter. -- BenRG 18:14, 8 July 2006 (UTC)


 * Hi Ben, thanks for the pointer -- that was a great laugh: the "!"s are an dead Afshar giveaway :-) And yes, I realise that Afshar will never change his POV any more than the cranks that push the "luminiferous aether" (sci.physics taught me that many years ago), but modern Galilean relativity has a reasonable critiques section in spite of their activity.  As for linas, well who knows, he seems to have calmed at Wikipedia talk:WikiProject Physics over my additions claiming that they are merely "boring" (he is correct of course).  --Michael C. Price talk 19:15, 8 July 2006 (UTC)

Having been away for a few days I see that the history of the talk page shows rather disturbing posts. I find the personal attacks on me by anons and others quite disgraceful, and shall not dignify any of them by a response. As for the article edits by Michael, I will address them when I have more time. For now, I am still waiting for Michael's quotations and ref.s. Finally, I wish to thank CSTAR for the SProtection of the talk page, and Linas for his attempts to ensure objectivity and NPOV of the article.-- Prof. Afshar 04:08, 12 July 2006 (UTC)
 * Indeed, let's focus on the substantive issue of the veracity of my article addition. As I asked Linas  here, what part of:
 * Bohr's philosophical views on the Complementarity Principle are generally seen in accordance with the Schrodinger wave equation. Since the latter is obeyed in Afshar's experiment it is not obvious how complementarity can be violated.


 * The modern understanding of quantum decoherence and its destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from quantum to classical. As such there is no need, in the decoherence view, for an a priori introduction of a classical-quantum divide as enshrined by complementarity.  Any experiment that claims to violate complementarity needs to address this issue.


 * do you regard as unsupported by the literature? Unspecific claims of OR are not acceptable -- I want specific claims that logically address the issues.  For instance the first point stands unless you think that Bohr's philosophical views on the Complementarity Principle are not in accordance with the Schrodinger wave equation.  Is this what you think?  The second points stands unless you think that quantum decoherence and its destruction of quantum interference does not provides a mechanism for understanding the appearance of wavefunction collapse and the transition from quantum to classical.  Is this what you think?  See refs at decoherence --Michael C. Price talk 06:33, 12 July 2006 (UTC)

Here I have added the supporting explicit quotations that Afshar requests to the article, to save readers the trouble of trawling through the voluminous external links supplied. I am only sorry that they couldn't come from a peer reviewed publication -- if/when the experiment is finally published in a peer review journal perhaps this will change. --Michael C. Price talk 07:52, 12 July 2006 (UTC)


 * Dear Michael, you must be joking! What you placed on the article page is not considered to be reference material. Let's settle the issue in the talk page first, then post, or remove whatever is necessary. Your flippant attitude and behavior reminds me of some of the anons. If you insist on this kind of behavior I will request an arbitration. I request that you restrain yourself and wait for my response here when I have more time. -- Prof. Afshar 13:22, 12 July 2006 (UTC)

Reference(s) for Michael Price's edits
Dear Michael, you claim that your assertions in the edits you made to the article are popular views and must therefore have existed prior to my work. Please give the proper reference from peer-reviewed publications that predates my experiment. Anything less would simply not be considered a valid reference by any expert. -- Prof. Afshar 13:26, 12 July 2006 (UTC)
 * You requested the direct quotations, and they are important in demonstrating that my additions are not just my views. By your same logic all the external links should be removed (which the quotes were extracted from) along with the rest of your entire article, which also has not been published in a peer-reviewed journal (which is the only reason why no peer-reviewed critiques are available).


 * What distinguishes a crank from a scientist is their handling of criticism -- all you are demonstrating by your inability to tolerate criticism is that you are a crank and that your defensive edits are vandalism. BTW I see you now request that any counter-evidence pre-date your experiment -- what a shameless shifting of the goalposts.  By all means raise a RfC, but you might not be happy with results.  --Michael C. Price talk 13:35, 12 July 2006 (UTC)


 * Michael, please whatch your language. Your personal attacks are totally uncalled for and way out of bounds. I am requesting mediation, and will not be provoked by your taunts to behave similarly. Be civil please. You are supposed to get the argument settled in the talk page first and then add tect to the article. --Prof. Afshar 13:49, 12 July 2006 (UTC)
 * Afshar, please answer the issues raised. For instance the first critique point stands unless you think that Bohr's philosophical views on the Complementarity Principle are not in accordance with the Schrodinger wave equation.  Is this what you think?  And do you really need a reference for this?  The second critique points stands unless you think that quantum decoherence and its destruction of quantum interference does not provides a mechanism for understanding the appearance of wavefunction collapse and the transition from quantum to classical.  Is this what you think?  See refs (some which do pre-date your experiment, although why that is relevant I do not see) at decoherence.  --Michael C. Price talk 13:57, 12 July 2006 (UTC)


 * Unlike some on Wikipedia, I have a day job, so cannot respond right now. Please be patient. Will respond later today.--Afshar 14:06, 12 July 2006 (UTC)


 * I'm with Michael; the demand that the references be from peer-reviewed sources seems unreasonable, given that the experiment itself has not been published in a peer-reviewed journal. If only one POV is presented in the article, and the reader must follow some external links to get the other POV, the article doesn't seem balanced. Pfalstad 22:22, 12 July 2006 (UTC)


 * Michael, I've had a tragic death in the family and am not in the right frame of mind for the discussion at this moment, but just for future discussion (tomorrow perhaps), what do you consider Complementarity to say about which-way experiments? How does Wheeler's delayed choice experiment involving the imaging lens (which is the basis of my experiment) define the Complementary observables? These are very important points if we are to avoid vagueness in our statements. Regards.-- Prof. Afshar 03:38, 13 July 2006 (UTC)


 * I'm sorry to hear about Shahriar's tragedy. As for Wheeler delayed choice experiment, we must be careful not to discuss the validity of QM itself.  However there does seem to overlap with this experiment worth commenting on.  Also the delayed choice quantum eraser seems relevant.  It opens with:
 * A delayed choice quantum eraser is a combination between a quantum eraser experiment and Wheeler's delayed choice experiment. This experiment has actually been performed and published by Yoon-Ho Kim, R. Yu, S.P. Kulik, Y.H. Shih, and Marlan O. Scully Phys.Rev.Lett. 84 1-5 (2000).  This experiment was designed to investigate a very peculiar result of the well known double slit experiment of quantum mechanics, the dual wave particle nature of light, and in fact all matter.
 * Marlan O. Scully already appears as a reference to the Afshar experiment as :
 * Bethold-Georg Englert, Marlan O. Scully & Herbert Walther, Quantum Optical Tests of Complementarity, Nature, Vol 351, pp 111-116 (9 May 1991). Demonstrates that quantum interference effects are destroyed by irreversible object-apparatus correlations ("measurement"), not by Heisenberg's uncertainty principle itself.  See also The Duality in Matter and Light Scientific American, (December 1994)
 * --Michael C. Price talk 09:24, 13 July 2006 (UTC)

I have created a Englert-Greenberger duality relation page and moved the details there from Complementarity which is about Bohr's views. --Michael C. Price talk 17:16, 13 July 2006 (UTC)

Linas asked for a more specific critique, which I have provided. It draws upon Englert-Greenberger duality relation page. I have also clarified a few other points to provide more balance. With these changes I am happy that this article is neutral and have replaced the POV with an OR tag. When the experiment is published we can remove this tag as well. --Michael C. Price talk 10:29, 14 July 2006 (UTC)

Imaging slits or targeting detectors
A lot has been hapening here since I last visited. It's good to see the debates are still raging and people are still passionate about this experiment and what it means.

Have been reignited to speak in relation to Cramer's recent proposal to send messages back in time. If such were possible (ie. if we ignore for a moment that it's impossible) we could use such a technique to test the assumptions of whelcher weg experiments.

I propose the ultimate whelcher weg experiment to settle all disputes.

1. Set up a twin slit experiment with one particle at a time.

2. Next to slit A put a trigger that can block slit A at any designated moment.

3. Set up two detectors, one focused on slit A, and the other on slit B, ie. using a lens that selects only that wavelet coming from the respective slit.

4. When a particle is detected by detector B, compute the instant the particle was supposedly "in" slit B.

5. Send a signal back in time to that precise moment when the particle was in slit B. But use the signal to close slit A at that precise moment.

Using the results of this experiment, explain/predict:

a. why/if the retrocausally tiggered closure of slit A still results in an intensity drop in it's corresponding detector (ie. when compared to no closure at all).

b. Why/if it doesn't.

c. Why/if the intensity is found to drop in both detectors (my favourite).

Carl Looper 12 October 2006


 * Cramer's transactional, time travelling interpretation of QM is mathematically isomorphic to the conventional Schrodinger equation, so it can't have any causality-busting implications. --Michael C. Price talk 10:36, 12 October 2006 (UTC)


 * Apart from the problem of how one sends a signal back in time (the real problem) you'll notice that I've set up this experiment in such a way as to be consistent with Cramer's interpretation. A transacted wave is allowed to form between the source and detector B, and this time symmetric wave is left uninterrupted by the signal sent back in time to the trigger on slit A, ie. so as not to upset causality. - Carl


 * I should add that the causality between source and DetectorA is also unaffected (if we follow Cramer's model) since no transacted wave forms there (it forms only in B) - Carl


 * Sorry, but messages cannot be sent back in time via Cramer's transaction interpretation since, as I've already said, the TI is empirically indistinguishable from the conventional interpretations of QM. Afshar's experiment is also in conformance with the canonical interpretations, so the whole exercise is a dead duck.--Michael C. Price talk 23:23, 12 October 2006 (UTC)


 * I'm not using Cramers model to send signals back in time. Neither is Cramer. But his take on the Dopfer experiment doesn't rule out being able to do so. As already mentioned the big "if" is precisely the ability to send a signal back in time. But I have no model for this. So in the experiment I've left this unspecified. My question is, assuming the success of the Dopfer/Cramer experiment (which I can't see), what would be the predicted results of the above experiment. As far as I can tell the TI predicted results, if I understand Cramer's model, is that the rate of detections on DetectorA (it's "intensity") should either remain the same as would be the case if slitA remaining open throughout, and/or statistically different from the results of randomly opening/closing slit A (to distinguish a fake retrocausal switch). And if not why not? Is there some error in my interpretation of TI - and if so - what? - Carl


 * Dear Carl, I did have a conversation with John Cramer regarding his proposed experiment while I was at UWS for a talk a couple of months ago, and proved to him that his proposition won't work. He subsequently wrote another paper entitled "Dopfer show stopper" and e-mailed it to a number of colleagues. If you wish, drop me an line at afshar@rowan.edu, and I will forward it to you. As for Michael Price's comment that my experiment is "in conformance with the canonical interpretations"; two comments: (1) What exactly do you mean by "canonical", and what are those "canonical interpretations"? (2) It seems, in-fact, that the "duck" is pretty well and kicking, as it will soon start quacking the orthodoxy to a new low of indignation and uproar. I suggest you keep your shotgun well-oiled and ready for action again!) Regards. P.S. You may wish to read Paul O'Hara's recent paper on my experiment http://arxiv.org/abs/quant-ph/0608202. You may also wish to mention it in the article in an objective manner. Here's a hint from the paper: "...it seems to me that the Afshar experiment has succeeded in demonstrating that these two properties can co-exist simultaneously..." Prof. Afshar 02:28, 13 October 2006 (UTC)
 * By "in conformance with the canonical interpretations" I refer you to what Ole Steuernage, Lubos Motl and Bill Unruh say in this article. --Michael C. Price talk 05:54, 13 October 2006 (UTC)
 * Well, what is so "canonical" about what they say? Interestingly, they all differ from each other and negate the other's arguments if you bother to read their entire critiques. There are absolutely no "canonical" interpretations of QM, simply more common interpretations of QM formalism, and it is important to point out that all of these interpretations negate one another. Canonical arguments, on the other hand, are supposed to be mutually-consistent and should not negate one another! Regards. P.S. Ole Steuernage's argument is actually patently wrong as he has erred on the process of diffraction, and has not replied to me after more than a year on that error. I wouldn't mention him as a defendant of one's position if I were you. Afshar 06:51, 13 October 2006 (UTC)
 * Yes, the critics shouldn't contradict eachother. But do they?  The quotes offered in the article are mutually consistent.  Your claim that they "negate the other's arguments" is just that, a claim.  Since you have previously claimed that many-worlds violates conservation of momentum I think we are entitled to view your original research claims with extreme scepticism.  Ole Steuernage's silence can also be interpreted as meaning that he found your rebuttal not worth responding to.  --Michael C. Price talk 07:38, 13 October 2006 (UTC)


 * Wow, that was nice a little digressive hyperbole, but sadly it won't do here. You still haven't answered my question regarding the "canonical" interpretations. As for Motl, he conceded after a number of back and forth communications that "I would agree with you that Prof. Bill Unruh's setup is not equivalent [to yours]," (i.e. he disagreed with his argument.) It's on his weblog if you care to look. You, like many other critics, liberally misquote me, and that really does not help your case. I have never said that MWI violates the conservation of momentum (CM). What I said was that David Deutsch's argument regarding MWI in which "shadow" photons from a parallel universe exchange momentum with "tangible" photons in our universe certainly does violate CM in our universe, and there isn't the slightest experimental evidence for it. I challenge you to refute my claim regarding Deutsch's statement in his book "The Fabric of Reality." As regards your view on Ole’s lack of response, that "he found [my] rebuttal not worth responding to", all I can say is that that does not seem to have stopped you from responding! Who knows, you may wish to follow suite. Regards. Afshar 16:00, 13 October 2006 (UTC)


 * Actually what you said was "from my limited exposure to MWI, it does not even qualify as a viable theory because it seems to violate conservation of linear momentum in interference experiments". Note you did NOT say that Deutsch's explanation of it was invalid, but that the theory itself was defective.  Any physics undergraduate could tell you that no quantum theory can violate conservation of momentum, by Noether's theorem.  --Michael C. Price talk 01:08, 14 October 2006 (UTC)


 * Still haven't answered my question regarding "canonical interpretations", but I'll let that go, as you seem to ignore it. Now that you insist on using quotstions out of context, let me provide you with the context in which I said the above:


 * "I had never looked into MWI in the past, and my exposure at this time is only limited to what I can glean out of David Deutsch’s book “The Fabric of Reality”. Therefore, with the above caveats, I have the following comments:


 * I assume that based on MWI:


 * 1) All photons are like rain drops or billiard balls with a well-defined trajectory in each universe. (p. 35)
 * 2) Real photons are the ones that we observe directly in our experiments. (pp. 42-43)
 * 3) Real photons can pass through each other without an exchange of momentum. (p. 41)
 * 4) Shadow photons belong to parallel universes, and are “Real” in the corresponding universes and not the universe in which the “current” observer resides. (pp. 44-45)
 * 5) Interference Pattern (IP) is produced by the interaction of Real photons with Shadow photons.
 * 6) In order to produce the IP, the Real photon must be “deflected”, so there is an exchange of momentum between the Real and Shadow photons. (p. 49)
 * 7) Any effect of the Real photon that can provide “which-path” or “which-way” information must destroy interference, i.e. Complementarity is upheld by MWI) (p.50).


 * Comments:
 * I) I find it interesting that David does not even bring up the possibility of describing the IP as a result of interference of waves. As I mentioned in the past, Willis Lamb and Leonard Mandel as well as many others in the Stochastic Quantum Electrodynamics community have shown that one can explian the Photoelectric effect (as well as Compton scattering, etc.) by using a classical electromagnetic field (waves) interacting with quantized matter. In other words between the emission and absorption of photons, light can be described perfectly using Maxwell’s equations. There is absolutely no evidence for (1); every attempt to demonstrate photon trajectories, invariably bumps into the wave nature of light.
 * II) Why is it that Real photons do not exchange momentum with each other, but Real and Shadow photons do?
 * III) What is the mechanism for the exchange of momentum between the Real and Shadow photon? What is the coupling process, and is momentum conserved in this process?
 * IV) From the perspective of a Real observer, we must say that the Real photon one observes in an interference pattern was deflected on its path, such that it avoids the dark fringe. This necessitates a violation of Real momentum in our universe (world), unless the Shadow momentum from the Shadow photon can become Real in the process. This is an amazing statement: momentum can be created in our universe without it ever having a history here. This is a clear violation of the Law of Conservation of Momentum and Energy, and has NEVER been observed in any experiment." Source:http://irims.org/blog/index.php/questions?template=popup&p=23&c=1 posted on 01/21/05 @ 06:26.


 * I still stand by what I said regarding Deutsch’s argument on MWI, and again challenge you to refute the above argument. If you don't like Deutsch’s ideas on MWI, then criticize him not me! Regards.-- Prof. Afshar 05:15, 14 October 2006 (UTC)


 * A shame that your lengthly rebuttal of what you claim is DD's argument does not address the issue that your original comment was a critique of MWI, not of DD's interpretation of MWI. Ah well, attention to detail was never your forte, was it?  Misquoting yourself in an attempt to claim you were quoted out of context is also not a good debating tactic: I shall charitably assume this is another consequence of your inability to deal with incovenient but important details.  This is clearly going nowhere, best wishes.  --Michael C. Price talk 07:27, 14 October 2006 (UTC)


 * LOL... Any discerning individual can see what I have said, and how you dodge my questions and challenges, and appeal to amusing hyperbole. Good thing this whole thing is being kept as a record, so the future readers can also LOL. All joking aside, of course you are entitled to your self-righteous ideas, and thanks for your charity. B’Bye.-Afshar 15:38, 14 October 2006 (UTC)


 * thankes Prof Afshar. Have just posted an email to you.

Whether or not it is possible to send a signal back in time does not really affect the experiment as the experiment is only a "what if" experiment. We do not need to know how this is done. We might need to know how/if it can't be done but that's another story not necessarily answerable by current theory. The question is, if it were possible, what would TI predict? As I understand it, it would predict option B. And if not why not? The probability wave interpretation (Copenhagen) would predict option A, ie. that the triggered closure of slit A (irregardless of retrocausal source or just random source) would interrupt a CI wave in direct correlation with the rate and number of slit closures - thus causing a perfectly CI predictable drop in intensity in detector A (when compared to always open). We can argue that this is the result of our retrocausal signal changing the past. What we can't argue is that it demonstrates Cramer's transactional model That we can't yet perform this experiment, due to the failure of the Dopfer/Cramer proposal is beside the point. Or is it?

After all, models such as Cramers are asking us to imagine something like the scenario just presented - but how can we imagine it? The only way to do so is to imagine that one could send a signal back in time and perform the said experiment. But when I do this (send a signal back in time) I get either option A results (Copenhagen) or option C results, ie. I can't reproduce Cramer's results. Only if I drop the requirement for emperical results can I follow Cramer's model but then I don't get any results !!!!

My own model predicts option C results which I'll leave unexplained for a little while - until I work out why it's predicting such. Carl


 * In logic the inclusion of one logically impossible thing enables you to prove any logically impossible thing. Including time-travel (which may be logically impossible) in your thought experiment may have the same effect as in logic.  I suggest you debate this at the transactional interpretation talk page.  --Michael C. Price talk 08:12, 13 October 2006 (UTC)

Time travel is not illogical per se although some versions are. But that's beside the point. The probability interpretation of QM can be regarded quite correctly as illogical. But such illogicity doesn't make it a candidate for the rubbish bin (which is my argument). And the transactional model is very logical yet strangely redundant - unless you can imagine sending messages into the past. And while I can't imagine how this is possible I can certainly set up placeholders in my models for such. As for whether this discussion belongs here I think you'll find these questions are interconnected. You'll find I've dropped some ideas over there as well. And you can check out my comments in the archive of the debate here (which gets a little hot in places) - Carl


 * Time travel may not be illogical (as you say, it depends which version you adopt -- Novikov consistency may be OK), but you need to identify which version you are adopting to avoid potential pathologies. But once again I must stress that whole time travel issue is irrelevant since the TIQM is mathematically and empirically isomorphic to mainstream QM, which lacks chronological acausality.  --Michael C. Price talk 14:31, 13 October 2006 (UTC)

The only time travel model I used was one which avoided the usual pathologys. Other than that I just allowed information created chronologically later to be channeled back to an earlier time. Keep in mind this is all happening in a computational simulation. But other than this placeholder I connected in CI, TI and my own model according to the way they are philosphically constructed. My own model is quasi-emperical but more on that later. And where you use the word "irrelevant" I use the word "redundant" so you see we can agree.

So it might surprise you I've constructed such a mind experiment in the first place. Well, why do we need to interpret QM at all - given it's mathematical formalism? Well, the mathematical formalism is not entirely the origin of the various interpretations. The origin is to be found firstly in the data, secondly bewilderment and thirdly, a mathematical solution (historically speaking). Where does the bewilderment come from? It comes from an attempt to interpret the data whether we understand that is what we're doing or not. This is very natural. Without interpretation data is indistinguishable from noise. Unless we cross the interpretational threshold (if only contingently) we can not reach the mathematical formalism - unless of course, someone else has already done so for us (eg. Heisenberg, Bohr, Einstein).

The interpretational methodolgy adopted by Heisenberg et al was radically emperical and owed everything to a history of such. But they still had to find that methodolgy. They couldn't look it up in a textbook. Neither was it an automatic intuition. The dominant methodology of the day was what we now call (in abbreviated form) "classical" or "rational" or "Cartesian" or "Platonic" and all this mitigated against a solution. But empericism was no less classical. It acan be traced back to the Stoic philosophers. In any case the point is that once a philosophy was found the formalism became that much easier to intuit/construct. But the formalism itself can't alleviate any bewilderment. It's utilitarian success doesn't make it anymore intuitive. What does make it intuitive, and this requires practice, is learning the various historys of thought - to see how one can arrive at a bizzare theory that both works and can be understood as not so bizzare after all. Or produce/consume alternatives such as the transactional interpretation which attempt to reconnect classicism - and do so quite well. But sort of arrive too late. But we don't know that for sure - especially if we ride the fence between radical empericism on the one hand and radical rationalism on the other.

This all said we might think - oh ok - well we don't have to think about all this stuff anymore because it's already been done for us. We can abbreviate it down to a few rules of thumb such as "oh that's emperically equivalent" or that's "mathematically equivalent" as if that was all one had to say or think to solve these problems. I don't think so.

Carl