Talk:Afshar experiment

OK, page created. I consolidated information which was spread (in many case, as multiple verbatum or near-verbatum copies of the same information) across many pages. The pages I edited to consolidate this information include:

• Wavefunction collapse
• Copenhagen interpretation of quantum mechanics
• Double-slit experiment
• Niels Bohr
• Wave-particle duality
• Bohr-Einstein debates
• Complementarity
• Transactional interpretation (Minor change: Link updated)
• Interpretation of quantum mechanics

I also removed red links to other suggested names for this page.

Next: Get rid of some links from Double-slit experiment which only apply to the Afshar experiment. Samboy 10:26, 21 Dec 2004 (UTC)

Done. Samboy 12:30, 21 Dec 2004 (UTC)

Afshar Experiment: A Dissenting Opinion

The Afshar experiment demonstrates that a coherent path distribution must be assumed to predict the number of photons incident on measurement spaces where path information is being observed, but it does not demonstrate that the coherent path distribution is actually realized across the surface of measurement spaces where path information is being observed.

All Figure number references in this article are references to Afshar’s Figure numbers in his paper “Sharp complementary wave and particle behaviours in the same welcher weg experiment”: http://www.irims.org/quant-ph/030503/

In Afshar’s experiment, the two holes can be considered emitters in the sense that he pumps photons through these two holes with his laser, and these photons have to go somewhere. Assuming the Copenhagen Interpretation of different path distribution functions (coherent versus decoherent) for different type of measurements (visibility versus path information), one might ask the question how do these photons get distributed in experiments involving complementary measurement spaces (i.e. how many photons get mapped into each measurement space). This question is also relevant in an experiment that involves only a single measurement space where path information is being measured. The answer of course is that a global coherent path distribution function across all measurement spaces must be assumed to predict the photons incident on each measurement space. The number of photons incident on a measurement space is predicted by integration of the global coherent path distribution function across the surface of the measurement space. But the Copenhagen Interpretation indicates the predicted number of photons incident on a measurement space where we are measuring path information don’t actually exhibit a coherent distribution locally.

So when Afshar says that he has visibility of interference on the photons incident on the lens, if he means that a coherent distribution predicts the number of photons incident on the lens surface, then this is correct. But if he is saying that the photons incident on the lens surface actually exhibit a local coherent distribution across the surface of the lens, then this is incorrect.

In Afshar’s experiment there are 13 measurement spaces. There are 6 measurement spaces where visibility information is being observed corresponding to the 6 wires. There are 7 measurement spaces where path information is being observed corresponding to the 7 portions of the lens segmented by the wires. The number of photons incident on each of the wires is very low because the wires are very thin and Afshar has placed them at the point of maximum destructive interference of the coherent path distribution function. The number of photons incident on each of the lens segments can be predicted by integration of the coherent path distribution function across the face of the lens segment. If the results for all of the lens segments are added up, the result is very close to the value for the whole lens when the wires are absent, since only the portions of the total lens where there is maximum deconstructive interference in the coherent path distribution function are omitted in this integration process.

Afshar’s interpretation of his experiment seems to be that since the wires are very thin and he has carefully placed them at the points of maximum destructive interference, he can treat his experiment as a single measurement space. Since he is observing interference in the photons incident at the wires, he concludes that there must also be interference present in the photons incident on the lens, since he believes both sets of photons are part of the same measurement space.

Even though the wires are very thin, the photons incident on the wires must be treated separately from the photons incident on the lens, since different types of measurements are being made in the two cases, and therefore the photons exhibit different behaviors for the two cases. For the photons incident on the wires, visibility information is being observed, and therefore the photons incident on the wires go through both holes with a corresponding coherent path distribution that exhibits interference in the vicinity of the wires. For the photons incident on the surface of the lens, path information is being observed, and therefore the photons incident on the lens only go through one hole with a corresponding decoherent path distribution.

The argument that the local path distribution across each of the 7 lens segments must be decoherent consists of the following four points:

1) The photons only go through one hole and are resolved at the detectors. Therefore any interference pattern in front of the lens cannot be explained by self-interference.

2) The only other way to explain a coherent path distribution in front of the lens is for a single hole to be emitting a coherent path distribution function. Hopefully we would all agree that this is about as likely as hearing the sound of one hand clapping.

3) If a single hole is (somehow magically) emitting a coherent path distribution function, then it would manifest itself in an interference pattern at the detector image.

4) Since there is no interference pattern at the detector image in Figure 8a, a single hole must not (somehow magically) be emitting a coherent path distribution function.

The third point above is illustrated by Figure 8b where Afshar has induced some of the characteristics of a coherent distribution sourced by a single hole by placing the wires in front of the lens at the points of maximum destructive interference. The image in Figure 8b clearly indicates interference at the detector. The interference pattern is also still clearly visible in Figure 8c, but it does seem to be attenuated somewhat from Figure 8b. Afshar’s explanation for this attenuation is that less photons are incident on the wires in Figure 8c than in Figure 8b, which is certainly true. In summary, Figures 8b and 8c indicate an interference pattern, but this interference is the result of placing the wires in front of the lens. Figure 8a illustrates clearly that there is no interference pattern at the detector without the wires present.

So how does Afshar explain his claim of a coherent distribution across the face of the lens? His explanation seems to be a superposition behavior in the neighborhood of the holes (that the photon goes through both holes exhibiting interference and it also goes through only one hole exhibiting path information). There is a superposition of states before the wave function collapses. Before the wave function collapses, there is a possibility that the photon goes through both holes with a corresponding coherent path distribution, and there is the possibility that the photon goes through one hole with a corresponding decoherent path distribution. Afshar seems to be assuming a superposition of two states at the two holes, but only a single potential path distribution. When we make an observation, the wave function will collapse in a way that depends on the nature of the measurement we are making. If we are measuring visibility information, the wave function will collapse such that the photon goes through both holes with a corresponding coherent path distribution. If we are measuring path information, the wave function will collapse such that the photon goes through one hole with a corresponding decoherent path distribution.

Afshar attributes far too much magic to the thickness and placement of his wires. A couple of examples with different thickness and placement are provided below to illustrate this point. Both of these examples assume a peak-to-peak distance of u = 1.4 mm for the consecutive fringes similar to Afshar’s first experiment illustrated in Figure 1.

For the first example, replace the wires with thin strips with a width of 1.4 mm leaving these strips centered about the maximum point of deconstructive interference. These strips will block some of the portions of the lens where the value for a coherent path distribution is less than the value for a decoherent path distribution (i.e. some of the valleys of a coherent distribution). All portions of the lens where the value for a coherent path distribution is greater than the value for a decoherent path distribution will be left exposed (i.e. all peaks of a coherent distribution). Next determine the predicted attenuation of the radiant flux at the image based on a decoherent path distribution either by calculation, simulation, or experimental measurement. Finally open the second hole and measure the actual attenuation in radiant flux at the image and compare with the value predicted in the previous step. The measured results will be much less than the value predicted by assuming a decoherent path distribution.

For the second example, keep these same strips, but move them to a position where they are centered about the peaks of a coherent distribution instead of the valleys of a coherent distribution. These strips will now block some portions of the lens where the value for a coherent path distribution is greater than the value for a decoherent path distribution (i.e. some of the peaks of a coherent distribution). All portions of the lens where the value for a coherent path distribution is less than the value for a decoherent path distribution will be left exposed (i.e. all of the valleys of a coherent distribution). Go through all of the same steps as in the first example. This time the measured results for the reduction in radiant flux at the image will be much greater than the value predicted by assuming a decoherent path distribution.

Both of these examples demonstrate the same results as the Afshar experiment (i.e. a coherent path distribution function must be assumed to prediction the reduction in photons incident on the detectors). Therefore there is no magic in using very thin wires placed at the points of maximum deconstructive interference.

In summary, the Afshar experiment demonstrates that a coherent path distribution function must be assumed to predict the number of photons incident on measurement spaces where path information is being observed. According to the Copenhagen interpretation, the assumed coherent path distribution function actually collapses into a decoherent path distribution function across the surface of measurement spaces where path information is being observed. The Afshar experiment provides no evidence that the Copenhagen interpretation is incorrect.

Originally contributed by User:63.226.32.16 to Talk:Double-slit_Experiment; I copied it here since it is appropriate to place here Samboy 19:38, 22 Dec 2004 (UTC)

Afshar's Response

The bottom line for the above Dissenting Opinion is the following false conclusion (quoted):

"According to the Copenhagen interpretation, the assumed coherent path distribution function actually collapses into a decoherent path distribution function."

Unfortunately, the major error in this argument is a misunderstanding of what the Wavefunction collapse actually means. Without going into mathematical details, a coherent superposition state can only collapse into an observable with a coherent distribution when a measurement is made. There is no "collapse" from a coherent wavefunction to a decoherent state because upon measurement a coherent wavefunation Psi is mapped into an observable wihtin |Psi|^2 via a projection, and not into some other decoherent distibution, say |Psi_1|^2 + |Psi_2|^2 . If the above quotation were true, then we could not observe an interference pattern in a double slit experiment, or immediately after the wires in my experiment, by direct observation, but we do! We cannot change the definition of wavefunction collpase to an arbitrary and mathematically inaccurate one, just to save Complementarity! Afshar 00:06, 23 Dec 2004 (UTC)

It is quite telling that the anonymous writer of the Dissenting Opinion (whose name is actually Alex), having now realized that his definition of the wavefunction collapse was indeed erroneous, has again attempted to “correct”his conclusion by replacing the pervious version with the following: "According to the Copenhagen interpretation, the photons predicted by the assumed coherent path distribution function actually exhibit a decoherent path distribution function locally across the surface of measurement spaces where path information is being observed." I'm afraid, the more he awkwardly tries to avoid self-contradiction, the more his lack knowledge on even the most rudimentary QM formalism and language becomes apparent. There is no such thing as "coherent path distribution function" in QM. I suggest that he formally study QM before making more clumsy statements. Need I say more?! Afshar 07:50, 23 Dec 2004 (UTC)

The school between Central and Porter squares

Of course one could miss the stop, and coming from Kendall sq end up say in Davis sq or Alewife. And even if by luck, one did get off on the right stop, and succesfully finding one's way out of the station one might think one ended up instead in an upscale urban mall complete with the Gap and a really fancy Barnes and Noble (which actually has real books on math).

But why is it necessary to mention this place in the very first sentence of the article? CSTAR 22:55, 23 Dec 2004 (UTC)

Are you sure this has to do with the Afshar experiment? Samboy 23:43, 23 Dec 2004 (UTC)

Yeah. it's a snarky comment at the abundant mentions of Harvard(on at leat two sides). Is it really necessary? CSTAR 23:49, 23 Dec 2004 (UTC)

Yes! Thanks for the graphics. Afshar 23:49, 23 Dec 2004 (UTC)

The pictures look great

This article looks great with the pictures and the mathematical formulas! Samboy 23:46, 23 Dec 2004 (UTC)

Definitions

The relevant definitions need to preceed (e.g. V , I_max) and so on, in order for the critique to make any sense to the non-specialist reader of the article. CSTAR 00:02, 24 Dec 2004 (UTC)

Where to start?

The article keeps saying that Afshar's results are incompatible with quantum mechanics, that Unruh challenged and led some to doubt Afshar's results, and that if Afshar's results are correct then they have far-reaching implications. As far as I can tell, this is not right. It seems to be Afshar's interpretation of the results, and indeed his understanding of quantum mechanics, which are in question. Unruh's write-up, for example, concludes as follows: "I think Bohr would have had no problem whatsoever with this experiment within his interpretation. Nor would any other interpretation of quantum mechanics. It is simply another manifestation of the admittedly strange, but utterly comprehensible (it can be calculated with exquisite precision), nature of quantum mechanics." The current wording gives quite a misleading impression. -- Reuben 03:03, 3 Feb 2005 (UTC)

• Dear Reuben, you say above: "The article keeps saying that Afshar's results are incompatible with quantum mechanics." I can only conclude that you have not read the article carefully. Where exactly is such an assertion made in the article?! As I have said many times in different interviews, my experiment indeed confirms QM formalism, but it disproves Bohr's Complementarity by showing that his "principle" does not follow from QM formalism at all. Sorry, but there is no misleading language here! --Afshar 03:54, 3 Feb 2005 (UTC)

• Fine, it doesn't say "incompatible with quantum mechanics." To be precise, it says "the Copenhagen interpretation" instead of "quantum mechanics." It does say the following, all of which are misleading.

"If his results are verified, it has far-reaching implications for the understanding of the quantum world, and invalidates the Copenhagen interpretation."

"On August 7, 2004, Bill Unruh presented an argument in which he claims to disprove Afshar's results."

"He demonstrates that his experiment is consistent with the Copenhagen interpretation and, on that basis, argues that Afshar's results are incorrect."

It's not any experimental results that are in question, it's Afshar's understanding of them. -- Reuben 04:47, 3 Feb 2005 (UTC)

• Naturally, you should read "results" as representing both novel experimental observations and novel theoretical arguments presented in the preprint. And no, Copenhagen interpretation is certainly not the same as quantum mechanics... Afshar 06:20, 3 Feb 2005 (UTC)

• There's nothing particularly novel about the experimental results, since they are as you say exactly what quantum mechanics predicts. Only Afshar's interpretation and understanding is at issue. If that's what the article means, it should clearly say so. The current language is misleading. -- Reuben 06:38, 3 Feb 2005 (UTC)

• You may wish to look up the adjective "novel" in a dictionary. Simply because a particular line of argument follows from an already accepted formalism, does not mean it is not a novel one! Einstein's Special Relativity was implicit in Maxwell's equations, but it was aptly considered as a novel result. Edison’s light bulb also followed from Faraday’s work, but it was a real invention… The non-perturbative measurement scheme introduced for the first time in my preprint is indeed a novel concept with no precedence in the literature. If you wish to dispute my claim, I would appreciate a reference please. Afshar 07:05, 3 Feb 2005 (UTC)

• The precedent would be passing a vertically polarized beam of light through a vertical polarizer, and then measuring the final polarization along an axis 45 degrees from the vertical. Your setup is formally equivalent. Your scheme is no more "non-perturbative measurement" than passing a vertically polarized beam through a vertical polarizer is. But on a more important note, you don't seem very interested in my suggestion for making the text less misleading. Why is that? -- Reuben 07:53, 3 Feb 2005 (UTC)

I don't really see how this is supposed to violate wavefunction collapse. Perhaps you can try to clarify. As I see it, the photon travels through the two slits, interferes, the interference pattern travels through the carefully arranged dark-fringe wires, and then the photon collapses upon being detected at one of the detectors. Now, obviously if the wavefunction collapse occurred at the time of measurement, then that photon has reached that detector and so possibility of it having been stopped by the wires is erased. It seems that the argument is being made that because the path of the photon is being determined, that somehow it should go back in time and reestablish a chance to collide with the wire. But this does not seem to logically follow. In a standard delayed choice experiment, the path the photon took is selectively determined after the photon has already passed through the slits, but this at no point goes back in time and arranges something inconsistent with the measurement that was made. So since in order for collapse to occur, the photon has to strike the detector, that collapse already rules out the possibility that it struck the wire. The interference pattern at the detector is only determined by the past of the photon, not the future, because just like in the delayed choice experiment, the detector arrangement could be replaced by a screen. — Cortonin | Talk 06:40, 3 Feb 2005 (UTC)

• Please post your question in my weblog. I will reply to it there and then make an addition to the Wiki article to include the wavefunction collapse issue. We are conducting another experiment which directly addresses your concern. I may be able to discuss it in April.--Afshar 06:49, 3 Feb 2005 (UTC)

Well if it doesn't yet address that wavefunction collapse issue, then maybe we should avoid saying it violates wavefunction collapse on Wikipedia until the further experiments are finished. — Cortonin | Talk 06:54, 3 Feb 2005 (UTC)

Please do take a look at my weblog, Cramer's article and my NPR interview. The mention of the collapse is quite justified, and I will improve the article further. I do not think it should be removed just because the article is a live one! --Afshar 07:14, 3 Feb 2005 (UTC)

I read every mention of collapse on the weblog, and no justification of the completed and reported experiment disputing collapse is made. Instead, promises are made for future work and a future experiment which would clearly show this. I think this is great, and I would love to read about it, but the fact remains that we shouldn't call things concluded on Wikipedia before the experiments which will clearly do so are actually completed and reported. It's the obligation of the article to document and reason out why said experiment says wavefunction collapse is incorrect. If it can't do that yet, then it shouldn't say that yet. — Cortonin | Talk 07:49, 3 Feb 2005 (UTC)

Weblog Entries

"Addendum: A brief response to Afshar's criticism can be found at http://www.physicsforums.com/archive/t-62460_Afshar_2_slit_experiment--peer_review.html (see rkastner's third posting)"

I moved the above entry by 70.21.61.81 to this page, simply beacuse I have not yet responded to Kastner on the main Wiki page. After I enter my rebuttal, we can have Kastner's response to my official rebuttal. Let's not replace Wiki entries with Weblog links. Thanks! --Afshar | Talk 04:28, 18 Mar 2005 (UTC)

A natural language restatement of Kastner's interpretation

The problem with asserting that this experiment rules out either the Many-worlds interpretation, or the Copenhagen Interpretation's Complementarity principle, is the assumption that, because with only one slit open the lenses and detectors provide welcher weg ("which way" or "which path") information, they will also do so with both slits open. This is the assumption of the principle of locality, and locality has been disproven (though perhaps not conclusively, according to some opinions) by Alain Aspect's implementation of the EPR experiment.

The photons remain in the entangled state until they encounter the detectors; at that point, they apparently make the welcher weg choice. However, this presumes that they had a path all along. This cannot have been the case, because otherwise they would have interacted with the wires. And in fact, in the one-slit-open case, they do interact with the wires, and detection at one detector does represent welcher weg information. But despite the apparently intuitive fact that when they choose one detector and not the other it must represent welcher weg information because of the measurement with only one slit open, it actually does not; this is due to a non-local interaction.

Consider the EPR experiment. Albert Einstein, Boris Podolsky, and Nathan Rosen believed that they had shown that either the particles must have had spins in particular axes all along, a violation of the Heisenberg Uncertainty Principle, or that the wavefunction collapse involved a violation of local realism at the time of measurement, and they maintained that the second was impossible. They were in fact correct in their first assertion, but they were incorrect in their second assertion. What they could not have foreseen was that John Stewart Bell would devise Bell's Theorem and show that the values could not have existed prior to the measurement, thus showing that non-local interaction actually takes place.

In the Afshar experiment, the non-local interaction is at the point of measurement, where the photon chooses one or the other detector. In this case, the non-local interaction causes the photon to manifest at one detector and not the other; this is called "wavefunction collapse" in the Copenhagen Interpretation. This is a common description in that interpretation of particle detection in general. The wavefunction propagates until a detection occurs. At that instant, a non-local interaction takes place, and the particle is detected at a particular ___location; this implies that the particle simultaneously cannot be anywhere else. If we include "the Andromeda Galaxy" in the definition of "anywhere else," this requires an instantaneous transmission of welcher weg information to the Andromeda Galaxy in violation of the absolute speed of light limit postulate of Special Relativity. 66.114.138.239

• Moved this entry by 66.114.138.239 here because it contains major errors. i.g. photons are not in a entangled state, as there is only one photon at a time in the system. Locality is not the reason why we consider the images as provinding which-way information, it is the conservation laws. Too many errors too little time to discuss them...--Afshar | Talk 02:54, 08 Apr 2005 (UTC)

Georgiev's bust to Afshar's interpretation

Certainly there is error in Afshar’s interpretation, and the problem is that he is claiming without proof that there is which way information even when there is no grid before the lens. In order to explain where Afshar is wrong let us present the following scenario:

You have two identical baskets A and B with black ink. You have identical empty baskets A’ and B’ and you have the following two possibilities:

Case (i): you transfer the ink from A into A’ and the ink from B into B’

Case (ii): you transfer the ink from A by half into A’ and B’ and similarly you transfer the ink from B by half into B’ and A’.

If you look only the final state A’ and B’ you cannot determine which of the scenarios did take place. In the case (i) you have one-to-one correspondence between A and A’, as well as between B and B’. In the case (ii) you simply don’t have the above-suggested one-to-one correspondence between the baskets.

Actually the above example is showing clearly that you should know the function that converted A,B into A’,B’ in order to be capable to say is there one-to-one correspondence A->A’ and B->B’, or there is just holographic correspondence AB->A’B’ without correspondence between the elements of the initial and the final state.

In the first case (i) we can say that there is "which way" information, while in the second case (ii) we can say that there "isn't which way" information.

Now the argumentation of Afshar can be understood as circular proof or vicious circle. He takes as a ground the classical ray model of light in which the rays propagate in straight trajectories and then he concludes that A' is image of A, and B’ is image of B. Alas, in QM this is not the case and the production of the image A’B’ can be understood if we consider ONLY interference of waves. Even if there is no grid before the lens the image A’B’ can be considered as result of the following scheme of subsequent interferences: (a) Fresnel diffraction between AB and lens focal plane f1. (b) Then Fourier transform of the image entering f1, and output of Fourier transformed image at f2. (c)Second round of Fresnel diffraction between f2 and the image plane.

If AB is placed at distance a > 2f as is in Afshar’s experiment, then the distance between f2 and the image A’B’ is less than f. In the limiting case when a -> oo, the input at f1 is Fraunhofer diffraction (Fourier transformed image), and the lens performs Fourier transform resolving the two-pinhole image A’B’ at the lens focal plane f2.

But if the production of the image A’B’ can be explained by interference alone, then, even if there is no grid, you cannot claim that there is "which way" info [the scenario is analogous to case (ii) when you split the ink from baskets A and B in order to fill the baskets A' and B']. The strangest is that Afshar puts a grid, and thus sees that THERE IS INTERFERENCE. So the question is "Why Afshar insists that the light propagated along straight trajectory between AB and A’B’?". What he disproved is that classical ray optics is not valid, and in order to disprove complementarity Afshar must show that A’B’ cannot be produced by the interference series consisting of Fresnel diffraction + Fourier transform + Fresnel diffraction. But to start from classical ray optics in order to prove what Afshar wants to prove is simply pseudo-science.

The fact that the lens does not provide “which way” info one can read the paper [1]. A more technical version of Georgiev’s paper that busts Afshar’s interpretation can be found at [2].

Instead of conclusion we will point out that the current Wikipedia article begins with the phrase "The Afshar experiment is an optical which-way experiment ...", and it is exactly what Afshar needs to prove but he has not proven. Since the experimental setup is not "which-way experiment" the reader is lead into delusion from the very beginning.

Reply to Unruh question

Latest comment: 20 years ago3 comments2 people in discussion

Here is the question posed by Unruh. He asks "Yes, the lens acts as a "Fourier transform" device, but again so what?"

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From: Bill Unruh [3] Sent: Friday, April 29, 2005 1:33 PM To: Danko Georgiev

Again, your interpretation I agree makes no sense. The "which way" infomation IS there in the images, just as it is there in the original pinholes. I would certainly not advise him to give you the $1000 based on this argument. While he is wrong, he is not wrong in the way you have outlined it.

The fact that IF you were to place a screen before the lens, you would see an interference pattern, is irrelevant to whether or not the photons falling on the detectors convey "which way " information.

Yes there is a Airy disk. but so what. Yes, the lens acts as a "Fourier transform" device, but again so what. The natural propagation of the light also acts as a fourier transform. And the lens can be set up to compensage for the natural propagation transform to give you back the original image.

Bill Unruh

---

My reply is:

Dear Bill,

You simply don't understand the essence of my argument.

The existence of light "wave" implies that there is no "which way".

The application of Fourier transform between the two focal planes of the lens COMPLETELY MIXES THE TWO CHANNELS. In the Fourier transform you don't preserve the one-to-one mapping between the object and the image, but you introduce many-to-one mapping. Also the Fourier transform requires interference therefore if there is inteference of photon wavefunctions between the lens focal planes the final image certainly does not preserve the which way info. In order the interference to be absent between the two focal planes of the lens the photon wavefunctions for passage through slit A and B should be not coherent i.e. there must be already some "which way" marker as say different wavelength [color filter on the pinhole] or different polarization [polarization filter on the pinhole].

Danko

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• [Bill Unruh's response, from e-mail CC/ed to [e-mail] by Bill]

Since you decided to post an answer to a private reply to you to this whole list, I will respond in the same way.

a) EM waves are linear. Thus the image at the detectors is precisely the sum of the images from the waves emitted at the two slits. Those independent images are that if the wave came from pinhole 1, the image (yes, with diffraction pattern) falls entirely on detector 1, and the image from pinehole 2 falls entirely on detector 2. This is an elementary result of fourier optics. Yes, there is interference in the intermediate region, interference which comes from precisely the linearity of the waves, but that is irrelevant.

On the basis of your fourier optics, the Green's function of the EM field is precisely such that the image at detector 1 depends only and solely on the amplitude at slit 1, and that at detector 2 depends only and solely on that at slit 2.

b) What has "classical straight ray" arguments got to do with anything. Who discusses them but you? The argument is not based on "classical straight ray" arguments. It is based on the wave nature of light throughout.

You may be getting confused when the term "which way" is used. It is NOT which way the photon went between the slit and the detector. That is NOT what "which way" refers to. It refers to whether or not the photon came through slit 1 or slit 2. That is all. It has nothing to do with what the photon did in the space between the slits and the detectors. You may have gotten misled by the use of the word "way" in "which way" and thought that it referred to a complete path. It does not. In this context it would better be phrased as "which slit". It is ONLY which slit the light came out of that is being determined, not anything about how it travelled between the slit and the detector.

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• • Dear All,

Above is an exchange between Bill Unruh (a veteran physicist) and Danko Georgiev (AKA The Fake) in which Bill rejects his utter nonsense. Although Bill disagrees with me, I applaud his defense of truth, which in this case happens to be the defense of my arguments regarding which-way info in the images. The likes of Georgiev MUST be rejected and marginalized by all real scientists in the interest of scientific advancement, all personal differences aside. I have no problem with considering unorthodox ideas (after all some may consider me as unorthodox,) but after one realizes an individual is fake, and it takes no more than a couple of exchanges for a pro., the individual must be warned, and if stubborn, BANNED from professional forums. Therefore, I shall make recommendations to PhilSci and arXiv archives, as well as Wikipedia to put his name on their blacklist. I would also encourage you to do so. Sorry Danko, but you brought this unto yourself after my repeated warnings...--Afshar | Talk 15:46, 30 Apr 2005 (UTC)

• • Dear prof. Afshar,

here is the revised version of my paper, where I answer all of your non-sense questions.

http://www.geocities.com/dankomed/afshar.pdf

You have the opportunity to prepare your reply, before the paper officially appears in the june issue of the open acess journal NeuroQuantology. You previously said that you have lost "15 precious minutes from your life to read my critique". Well, you should lose 5 years more to study the basics of Quantum mechanics, becuase you don't understand its main mathematics. Read the above paper and you may understand that complementarity is not "interpretational aspect of QM" but it is a set of mathematical instructions that tell you how to calculate probabilities. My reply to Unruh could be found in the paper also.

Danko

What you have written is worth consideration, but please read wikiquette. Your treatment of Afshar is quite impolite, and it is better to work cooperatively here (and in fact, policy). (Afshar, I'd also suggest you read it, since it appears this has become heated.) — Cortonin | Talk 06:01, 10 May 2005 (UTC)Reply

Dear Cortonin, I couldn't care less about the manner in which Danko characterizes me. As any competent physicist would immediately notice, his "paper" is nothing but a hodge-podge of copied and pasted and mostly ill-understood concepts in Fourier optics, denounced by Unruh and myself (yes unfortunately I did read it). It is not impolite to call something what it is. It may be a bit blunt, but in this case, it is a no-brainer: Danko's "paper" is a joke, and an affront to serious physicists. As much as I respect the amateurs getting at it, I cannot ignore an ignorant person insisting on wrong concepts and total abuse of the professional lingo. What would you think if someone recommends that you use the Umbilical Cord to wrap up your gifts? Would you say "sure, a cord is a cord, is a cord"?! No, you would smile, and try to correct the individual, but if he still insists on that idea, you'd be entirely justified to dismiss him as a mere jester, deserving not a single minute of your time. Sadly, that is the case with Danko. Too sad really... Regards.--Afshar | Talk 13:26, 10 May 2005 (UTC)Reply

• • Dear Cortonin,

I am polite to anyone who is not using offences. I was blocked by Afshar, so I don't have access to his blog, and to his server, I was threatened to be reported to the PhilSci archive as ignorant, incompetent, and fake [as he calls me above]. I have personally required withdrawal of my paper from PhilSci, because I don't want to bother the editors of the PhilSci archive. They politely have sent me feedback fulfilling my request, and they announced that they will stop accepting papers on this topic, because the function of the archive is not to be a judge.

The problems in my first version were a lot, and most of them were because I did not use any mathematics. Now in the revised version posted at my account in geocities, i have included all the necessary math, showing that Afshar is popularizing wrong interpretation of QM [fraud?!]. I can say that it is not me who sounds impolite, it is Afshar the one who insisted that Einstein's Nobel prize should be taken back !!! This is total un-respect to other scientists who gave so much for the development of physics.

Danko

Dear Danko, I noticed you have withdrawn your submission from the PhilSci archive. If indeed you removed it on your own initiative, I applaud that. It is a good first step in the right direction. Also, I did see your "improved" paper, but it still suffers from the same shortcomings as the original one. At any rate, best of luck to you.--Afshar | Talk 14:11, 10 May 2005 (UTC)Reply

• • Dear prof. Afshar,

As I have said I personally have requested removal of my PhilSci paper. It is sad however that you repeatedly claim that I am a medical doctor, so that is why I am ignorant in physics. So far I have not seen any mathematical reply proving your thesis that there is 1:1 correspondence between a slit and a detector. In contrast I have provided a lot of mathematics, and if you really have read my revised paper you should be already competent about the fact that COMPLEMENTARITY TELLS US HOW TO MANIPULATE QUANTUM AMPLITUDES IN ORDER TO OBTAIN THE PROBABILITIES OF CERTAIN EVENTS. I have simply explained to you that your thesis insists that we observe |psi_1|^2 + |psi_2|^2 distribution [intensity distribution], while I claim that we actually have |psi_1 + psi_2|^2 distribution. If one follows your suggestion we should expect "clumping pattern" if your sigma_2 detector is put out of focus, while if my thesis is right I claim that we shall observe "interference" picture.

Please stop using offensive texts, noone profits from that. Just write down the mathematics proving your thesis.

Danko

Classical ray optics is not Quantum Mechanics

Dear prof. Afshar,

As I have added special section where I explain where Unruh is wrong, actually I also say that your error is essentially the same - you use the classical ray model of light and this is where your error comes from. In the discussion above you advised me to see the web page: http://webphysics.davidson.edu/applets/Optics/intro.html

and I have checked that link today. What everybody can see is exactly the CLASSICAL RAY MODEL OF LIGHT AND THE CLASSICAL MODEL OF LENS ACTION. Actually you tell me nothing new - I already have analogous figure in my revised paper. Soory to tell you but the classical formula 1/a + 1/b = 1/f, where a - distance to object, b - distance to image, f- focal length is not the only way to explain the production of images. I will give you simple counterexample, and i hope you will understand now how serious my critique is.

Suppose we have double lens system 1f-lens-1f-1f-lens-1f. The classical ray model will give you again right image of the object. Folowing this classical model you may consider that there is which way info. However the Fourier optics provides alternative explanation - you have double applicaion of Fourioer transform, so you end up with the same image as predicted by the classical model. However in this second case you don't have which way info.

Wish you nice reading of my paper. I am sure that it will not be losing of time by you.

Danko

for recent opinions or results from the ongoing discussion check also: http://www.geocities.com/dankomed/afshar.htm

Misc

Latest comment: 20 years ago1 comment1 person in discussion

My question is not related to Danko Georgiev, and please don't kill me because I am at the moment not a professional physics student (I am math and electrical engineering). It appears from the article that Unruh's main objection is that Afshar is interpreting two measurements as one in which the light acts as both a wave and a particle. Unruh says it is two different measurements and in one (the detector) it seems particle, and in the other it is a wave since the light is interfering around the wire. If Unruh is right, then what constitutes a legitimate measurement that would show a violation of complementarity? A single measurement in which you get wave and particle behavior? What does 'a single measurement' mean? Bananaclaw 03:05, 16 May 2005

Dear Bananaclaw, Please post your question on my Blog [4] , and I'll answer it there. Let's keep these questions off of the Wikipedia pages. Thanks.-- Afshar 17:11, 16 May 2005 (UTC)Reply

Dear Bananaclaw, If you check out any good textbook in optics you will see that classical ray optics is just approximation of wave optics. Concerning you question - yes, Afshar is right that IF there is which way, then the photons CANNOT avoid the grid and there WILL BE loss of photons. Unruh, as well as Motl are on the wrong way - my thesis: the PRESENCE OF THE GRID does not change anything in the experiment, while Unruh and Motl suggest that the grid "mixes the two channels - S1->D1 and S2->D2". Unruh and Motl theses are both wrong, and they are also wrong that without the grid there is "which way" info. If you don't believe me see the Yoon-Ho Kim's paper at arXiv: quant-ph/9903047, where is simply explained that LENS does not give you which way info in the double slit scenario. For more check my web paper. Danko [16 may 2005]

Major revision

Latest comment: 20 years ago4 comments2 people in discussion

I've attempted to cut the Gordian knot of confusion surrounding this experiment with a major rewrite/expansion of the article. There are three separate issues here:

• The claim that Afshar's experiment violates heuristic principles of complementarity. Since there is no precise statement of such principles, there is room here for reasonable people to disagree.

• The claim that Afshar's experiment contradicts certain interpretations of quantum mechanics. This is simply false. The only debate here is between those who understand the interpretations of quantum mechanics and those who do not. I don't know whether Afshar has made a claim along these lines. If he has, he probably has misunderstood what an "interpretation of quantum mechanics" is, based on the broader meaning of the word "interpretation" in English.

• The claim that Afshar's experiment contradicts a particular quantitative principle of complementarity, given in his paper. This is presumably either true or false, but I have no idea which. Can anyone fill in this information?

-- BenRG 13:28, 23 May 2005 (UTC)Reply

Dear BenRG, I moved your contributions to another page Afshar Experiment and the Interpretations of Quantum Mechanics dedicated to the interpretations issue. Since the paper itself is only concerned with the Complementarity issue, it would be helpful to separate the two to avoid confusion.-- Afshar 18:22, 23 May 2005 (UTC)Reply

Yes, the paper only discusses the complementarity issue. But surely you're aware that people are misrepresenting your work as having much broader implications for the interpretations of quantum mechanics. Given all the confusion and misinformation out there, the issue should certainly be addressed here. Furthermore, the article as it stands does not discuss only complementarity. It makes specific claims about the Copenhagen, many-worlds, and transactional interpretations, and those claims are false. At the very least allow me to replace that paragraph with a paragraph linking to the new article you created.

I notice that on the talk page for the new article, you describe my changes as biased. Please tell me specifically what you think is biased. I made a great effort to avoid any bias in what I wrote, and in fact I never expected you to disagree with it. -- BenRG 20:25, 23 May 2005 (UTC)Reply

Dear BenRG, Forgive me for this belated reply. I was tied up with rediculous exchange with Lumidek. Thank you for trying to clarify what I have and have not claimed. But since there are major errors in your contribution, please allow me to suggest my corrections as soon I can. For now, I am sure the page will not be deleted, which give me a chance to edit it. Best regards.--Afshar 13:28, 23 May 2005 (UTC)Reply

Original research

Latest comment: 20 years ago3 comments3 people in discussion

Most of the controversy section looks like an active debate on these pages, original research and so unencyclopedic at this stage. Should it be removed and replaced with a two line summary and external links?--Henrygb 16:41, 23 May 2005 (UTC)Reply

Dear Henrygb, According to Wikipedia guidlines, delineated in Original research, at worst Afshar experiment falls under the category of "the ideas [that] have become newsworthy: they have been independently reported in newspapers or news stories", due to the numerous news media oultlets that have covered this work, and hence can be posted on Wikipedia. However I do agree with your sentiment that the Controversy section seems somewhat like a back-and-forth discussion rather than an encyclopedic article. Perhaps the Controversy section should be put together along with the Afshar Experiment and the Interpretations of Quantum Mechanics page under a new page titled Afshar Experiment: Contoversy and Interpreations? I would appreciate your suggestions to that end.--Afshar 18:38, 23 May 2005 (UTC)Reply

For what it's worth, my recent contribution, since removed, was in part an attempt to summarize and encyclopedify the article. I left the existing back-and-forth discussion in place only because I didn't have time to read, understand and summarize it. I think this page should remain for the reasons Afshar gave: it is an experiment that has received a lot of publicity in the popular press. I think that people who come to Wikipedia for more information ought to find a well-written article which, among other things, explicitly mentions and corrects some of the errors that have been made in other media accounts. That's what I was (am) trying to do. -- BenRG 20:54, 23 May 2005 (UTC)Reply

Opponents and Proponents

Latest comment: 20 years ago3 comments2 people in discussion

Dear CSTAR, naming just the opponents (who have been answered by a proponent, i.e. Prof. John Cramer) is unfair. See this New Scientist link which shows the last reply to all those critics on August 21, 2004. The list of proponents of my conclusions includes Prof.s/Dr.s Antony Valentini, Dan Cole, Gregg Jaeger, Eduardo Flores, Ernst Knoesel, Robert Perry, Colin Bruce, F. Cardonea, R. Mignanib, W. Percontid, A. Petruccib, R. Scrimagliod, and many others whose names escape my memory right now. There is further evidence in support of my conclusions to be announced at the Vaxjo conference in a couple of weeks. This is a subject that by default all physicists would be opposed to at the beginning and as time progresses more are convinced as new evidence comes to light. Bottom line, naming Pro/Opponents at this time (beyond the critiques mentioned in the Controversy section) is unnecessary, and possibly misleading, especially in light of the fact that all those you listed have been shown to have been too rash in their response, as they did not have enough info on the experiment to make the correct judgment. Regards.--Afshar 06:01, 26 May 2005 (UTC)Reply

As you know, the August 21 letter was from John Cramer, the same individual who suggested your interpretation supported his transactional interpretation of QM. In any case your list of Prof.s/Dr.s are not individuals whose letters (if any) appeared in the New Scientist. It is only fair that the individuals included in the edit you reverted be named to balance your citing the New Scientist.

naming Pro/Opponents at this time (beyond the critiques mentioned in the Controversy section) is unnecessary, and possibly misleading,

This is disingenuous. Wikipedia is not meant to cover original research, and its inclusion here without appropriate disclaimer is misleading.

as they did not have enough info on the experiment to make the correct judgment.

Oh really? Are you the judge of that?

Based on this exchange, this article clearly does not satisfy the NPOV policy of WP.

Regards--CSTAR 11:37, 26 May 2005 (UTC)Reply

Dear CSTAR, It seems that now you are being judgmental! "This is disingenuous" NO!: (i) I am NOT sure if those individuals still believe what they wrote about before my refutation which John Cramer explained in his Aug. 21, 2004 letter to NS. That is why I said it may be misleading. You may wish to contact them before their names get permanently associated with this stance. (ii) "Oh really? Are you the judge of that?" YES! I am the judge of that and rightly so, BECAUSE: NS editors told me exclusively about the only clear shortcoming of the article, which was the fact that it did NOT mention the actual physical dimensions of the experiment and its components. Consequently most readers had assumed that the wires were as closely spaced as a regualr wire grating. In reality the spacing between the wires were 2-3 orders of magnitude larger than the spacing on a regular grating and thus produced much less beam mixing (hence no reduction in which-way info reliability). I am sure you were not aware of this fact (because I was the only one who got the e-mail from NS editors on this issue), and therefore you assumed that I was being biased in my decision regarding the inclusion of their names as opponents. Given YOU accept responsibility on possible assignment of views to individuals whose opinion may have changed after Cramer's letter, please go ahead and post those names. Further, if this remedy resolves your NPOV issue, please remove the flag, and if it doesn't tell me what else you have a problem with. Regards--Afshar 14:08, 26 May 2005 (UTC)Reply

Latest additions

Latest comment: 20 years ago5 comments2 people in discussion

Dear CSTAR,

Sorry for the fact that I was not logged in. Certainly the edit was mine. What I have really tried to edit initially is to put the NPOV banner on Afshar's article, but Afshar removed it. Since Afshar is writing his own biased entry, and since the main article is in a form of discusion, I decided to write down a "popular explanation" where Afshar is wrong. Also note that truth has nothing to do with encyclopedic style. Since the article describes the experiment, it should not have any of the interpretations neither Afshar's, nor anyone else's. And in order to be usable the intro that says that his experiment is "optical which way one" should be deleted, because this does not correspond to scientific truth. I will not try to recover my entry because I could be considered as biased therefore I hope that someone else will put a kind of banner on Afshar's article that will denote that Afshar's entry is used as advertisement, not as sci entry. Indeed by the conventional standards if someone promotes his own work in popular press, but if this work has not passed peer-reviewing and has not being published in orthodox sci journal, then the someone of interest possibly is charlatan or quack.

--Danko_Georgiev_MD 1:24, 27 May 2005 (+2.00 GMT)

The anonymous edits by User:212.91.163.193 (Danko Georgiev) hardly conform to an encyclopedic style. Regardless of the merit of the contents, it should be rewritten in a more suitable style or deleted.

The existence of this article and the problems which it has led to are a clear indication that the WP policy of no original research is a wise one. However, I am not a policeperson, so I won't request it be deleted.

Given that this article exists (unfortunately) , I don't care what Afshar's claims are. He could claim that the Moon is made of green cheese for all I care. However, given the constraint of this article's existence, the article should

• Report the fact of Afshar's experiment and his (and Cramer's) interpretation;
• Report that many qualified people don't believe his interpretation (I personally believe that MOST people believe his interpretation is wrong). In particular, the controversial (and in my opinion exceedingly unwise) decision of the New Scientist to feature this experiment should be counterbalanced with dissenting letters to the editor, of which there were many
• Report the experimental setup (roughly as is now the case)
• Report dissenting opinions with links to various webpages, rather than the extensive discussion. For Afshar's "rebuttals", reference to his weblog suffices.

This article should probably be placed on RfC.

--CSTAR 15:36, 26 May 2005 (UTC)Reply

I moved the comments by User:212.91.163.193 (Danko Georgiev) to the end of his original nonesense edits above. He has absolutely no credibility as outlined in the past by Unruh's rejection of his non-ideas in support of my analysis of the Fourier optics of imaging lens. As for your belief that "MOST people believe his interpretation is wrong" I must say that in my interactions with colleagues at different academic gatherings, I find that MOST have not formed an opinion yet. On New Scientist's decision to publish the article, you should know they interviewed many experts in the field and that this process took about 9 months. They asked me to respond to the experts' critique and after they were satisfied that the experts could not defend their objections, they decided to publish the article, that is hardly unwise. That said, I have found you more objective than other commentators here, and therefore would appreciate if you go ahead and implement those changes as you suggested, and I will react if I feel there is a factual error by alerting you.--Afshar 18:33, 26 May 2005 (UTC)Reply

Dear CSTAR, The issue of a lens (with no wires) providing which-way information in its image plane has been an accepted physical concept since Heisenberg's famous Microscope proof of the Uncertainty Principle. My setup in which there are no wires present is an exact replica of the one used by John Archibald Wheeler to demonstrate complementarity, and the images were considered to contain the which-way information. Both Unruh and Motl agree with the fact that the images produced by a lens (with no wires) provide which-way info. Danko is saying that regardless of the presence of the wires there is no which-way info. in the images, which is absolutely wrong as discussed by Unruh above. So, I have absolutely no problem with the which-way idea being ascribed to me, but it quite literally started with Heisenberg, and Bohr himself. I can give you the ref.s if you wish.--Afshar 00:28, 27 May 2005 (UTC)Reply

That's not Danko's point. Of course the term or concept which-way was not invented by you. However, to say as you claim the experiment is indeed a which way experiment is tantamount to accept your POV. Both Unruh and Motl agree with the fact that the images produced by a lens (with no wires) provide which-way info. Well yes that's clear and well-known. And reading Danko's latest entry and I find no support for you interpretation of it, i.e., Danko is saying that regardless of the presence of the wires there is no which-way info. However, whether or not that is what Danko meant is a Red-Herring.

Regards.--CSTAR 23:48, 26 May 2005 (UTC)Reply

CSTAR, we may be splitting hairs here, but I reworded the paragraph to make it accurate: because "which-way is preserved even when the wires are there" is indeed my idea, and so the paragraph is OK. I must point out again though, this is not an approval of Danko's erroneous point. In response to your "I find no support for your interpretation of it," just to make sure you realize I am not putting words into Danko's mouth here's a direct quote from above entries by Danko: "Certainly there is error in Afshar’s interpretation, and the problem is that he is claiming without proof that there is which way information even when there is no grid before the lens.--Afshar 01:08, 27 May 2005 (UTC)Reply

• Dear CSTAR and dear Afshar,

Yes, what I am claiming is that the image at the image plane of the lens does not contain "which way" info even if there is no grid. This is very clearly stated, and I don't understand what is not clear here. If someone of you wants to send me refs where this topic is discussed then I will glad to read them. This will just add more people to the fallacy list [so far Afshar, Motl, Unruh, and Drezet, fall in the category that defends the 'which way' without the grid]. This is however the main point - please prove it!!! i have provided clear mathematical definition of complementarity, and I have provided very concrete mathematics. Actually if there is 'which way' the density matrix must be mixed one, and if 'there is no which way' AS I CLAIM then the density matrix will be of pure state. The two different density matrices are in principle testable. In the first case you cannot recover interference in any way, in the second case you may clearly visualize interference! Simply if the density matrix is that of mixed state, then if you put the detector sigma_2 out-of-focus i.e. say two meters behind the image plane what you will see is just a clumping pattern [like the prediction of the Rayleigh formula], and IF I am right and the density matric is that of a pure state then out-of-focus you will obtain clear interference picture.

I have consulted all the current textbooks in QM and Quantum Computation, therefore I can argumentedly defend my position with mathematics. So far Afshar is blowing air under pressure, and I would like to ask him, please show where is your refuttal of my Fourier interpretation becase I have not seen it yet.

Danko Georgiev [28 may 2005]

• Questions for homework posed to Afshar:

• • 1. Formulate in mathematical language the complementarity principle [hint: I have done in the last section of this talk, so check you answer]

• • 2. Write down the density matrix for the 'which way' and the density matrix for 'no which way' [hint: read my paper [5]]

• • 3. Answer the question can the mixed state dendity matric be experimentally discerned from pure state density matrix [hint: in pure state the density matrix rho = rho^2, while if you have mixed state this equation does not hold].

• • 4. Tell me how you exactly prove that there is 'which way' if there is NO GRID before the lens. [hint: try not to use classical ray optics ; answer: in QM this is inprovable].

Self promotion and other issues

Latest comment: 20 years ago3 comments2 people in discussion

Though this article did not in a technical sense originate with Afshar (User:Samboy is listed as the originator), its contents were mostly material he had written about his experiment in other articles on WP. This article is not an autobiography (indeed very little information seems to be available to produce such an autobiography other than he is now visiting at Rowan University and is a member of IRIMIS); however, since it mostly pertains to Afshar's work, the policy Wikipedia:Autobiography is applicable here. In particular, the following paragraphs apply:

Similar principles apply to articles about works that you are primarily responsible for — the company you run, the website you started, the book you wrote. Use common sense.

Also, realize that anything you submit can be edited. Several autobiographical articles have been a source of dismay to their original authors after a period of editing by the community, and in at least three instances have been listed for deletion by their original authors. In some cases the article is kept even if the original author requests otherwise.

The other general policy issue I would like to point out is Wikipedia:No legal threats which Afshar has clearly violated above. The fact that Lubos Motl behaved in offensive ways is no excuse and should be dealt with in other ways (and preferably, completely ignored).

Wikipedia is not peer-reviewed and to pretend that the open nature of its editing process is a replacement for peer-review is nonsense. In particular, the controversy section with various pros and cons is not a reasonable place to evaluate Afshar's claims. The correct position should be complete skepticism until we have a peer-reviewed journal article in a scholarly physics journal. The active involvement of Afshar himself in the editing process of this article is highly suspect and should stop, in my opinion. Afshar is free to do what he likes, since I cannot nor can anybody else, short of a ban (which won't likely happen) enforce any of this.--CSTAR 02:32, 27 May 2005 (UTC)Reply

Dear CSTAR, "its contents were mostly material he [Afshar] had written about his experiment in other articles on WP" This is wrong! Look at the history of the mentioning of this experiment on Wikipeida. I had absolutely nothing to do with the very initial entries made on different mostly QM-related pages. I later tried to make the entries as accurate and fair as I could, evidenced by the inclusion of many different critics' comments, and added links that seemed relevant. "[Afshar's] editing process of this article is highly suspect and should stop" Surely you are not suggesting I have no right to set the facts straight?!--Afshar 04:02, 27 May 2005 (UTC)Reply

Dear Shahriar.

Surely you are not suggesting I have no right to set the facts straight?!

Don't frame the question, please. Fallacy of many questions.--CSTAR 03:22, 27 May 2005 (UTC)Reply

As to your other remark, I admit that tracing the source of every statement in this article is not something I have done. But your edit history in all the precedents to the current article is extensive, to say the least.--03:29, 27 May 2005 (UTC)

Mathematical clothing of complementarity

The complementarity principle TELLS US how to manipulate quantum amplitudes. This can be checked in my paper [6]. Briefly complementarity says:

1. If two wavefunctions (e.g. psi_1 and psi_2) are representing indistinguishable particle state then in order to compute the final probability you should add psi_1 + psi_2 and then square the sum. So P = |psi_1 + psi_2|^2

2. If you have distinguishable particle states then you first square then add. In this case P = |psi_1|^2 + |psi_2|^2

Therefore if Afshar busts complementarity THEN he busts the mathematical formalism of Quantum mechanics

This can be checked in any conventional textbook of Quantum Mechanics, so Afshar's claim that he disproves ONLY complementarity, but not Quantum Mechanical Formalism is ridiculous!!! So dear prof. Afshar, please write me down the mathematical structure of what you call complementarity. The complementarity principle as is understood in conventional textbooks is telling us how to manipulate quantum amplitudes in order to obtain probabilities. What you understand under the term complementarity is absolutely un-imaginable for me, and possibly for everyone who has studied QM.

Danko Georgiev (27 May 2005)

Final edits

Latest comment: 20 years ago1 comment1 person in discussion

I propose to remove the remainder after "complementarity" with something like

Various critiques of Afshar's claim have been posted on the internet by the well-known physicists Unruh of UBC link and Motl of Harvard link as well as others links. Afsher addresses some of these in his blog link.

A few words in the introduction bother me, particularly "many physicists" are skeptical which I believe should be "most physicists" are skeptical. However, I have not conducted a scientific poll, and I am sure that fact would be brought to my attention.

I hope this is the last I ever see of this page.

I also hope this serves as a lesson to anybody else that has the bright idea of creating a page on unpublished research. --CSTAR 16:33, 29 May 2005 (UTC)Reply

Concerning the Afshar experiment

There is one year already the physicist S. Afshar (see preprint) working at Harvard university realized a very controversial experiment in order to refute the famous principle of Niels Bohr called complementarity. This experiment was described in an article of the British journal New scientist [(2457, 24 juillet 2004)]. It was clear for me since the beginning that the result was badly interpreted and that the reasoning of Afshar was misleading.

In order to refute the claim of Afshar I would like, here, to explain briefly my reasoning.

File:Drezet.png

Principle of Afshar's experiment.

The optical experiment represented on the figure included is essentially an extension of a ‘gedanken’ experiment proposed by Wheeler and called the delayed choice experiment. A coherent light impinges on a screen containing two slits or apertures A and B. Light diffracts and produce interference fringes at large distance from the apertures. As well known we can use a lens L to observe these fringes in the focal plane (F). Alternatively we can decide to observe the image A' and B' of the holes in the image plane (I). This is simple and is only a problem of classical optics.

However difficulties arise if we consider the same problem with photon. Indeed a photon is a discrete entity which can produce a local click on a detector. If we suppose that light is made of particle how to explain the existence of the interference? This is the canonical problem called wave particle duality. Einstein and others, like de Broglie or Bohm, tried to justify this curiosity of nature but Bohr found a simple solution to this problem which is to dismiss the entire issue by avoiding any reference to objective reality. For Bohr and Heisenberg it is a complete non sense to search an explanation for such quantum behaviour. Indeed such explanation(s) could not be experimentally tested.

Bohr realized that effectively if you build up a model attributing a trajectory to photons then you should be able to observe experimentally these trajectories. If you can't do that your model is without any physical interest. However Bohr remarked that the observation of the path of the photon always disturbs the coherence of the wave and erase the interferences. In the present context we have the choice between detecting a photon in the image plane or in the focal plane. This means that we have the choice between using each photon to build up the images A' and B' ('which path' information) or the interferogram. But since a photon can not be absorbed twice we can not make the two observations with the same particle. This is the reason why Bohr called this property complementarity.

Now let go to the Afshar modification of the preceding experiment. Afshar decided to observe his photons in the image plane (I). Nevertheless he introduced in the focal plane a periodical grid of absorbing wires (in fact he worked just in front of the lens but this doesn't affect my reasoning). The wires are located at the exact minimum of the fringes. Naturally the experiment is not affected by this introduction because the intensity on the wires is close to zero producing consequently no additional disturbances or diffractions on the light propagation. The two spots in A' and B' are then unchanged.

However since no photon are absorbed this give us information on the intensity at the wires ___location. We know then that the probability for a photon to cross the section of the wire is null and this is already something. Afshar believes that this information is sufficient to prove the existence of fringes in the plane. He is wrong. Naturally he is however right saying that clearly the intensity can not be uniform in the focal plane. But he can not really say what the shape of the fringes in this plane is. Bohr’s principle speaks about physical observation not about metaphysical expectation. To define experimentally the fringes he should use other photons that the ones recorded in the image plane. If you need an analogy you can imagine the following situation. You are living in Paris and you can see from your beautiful flat (with a rent of 8000 $ per month) the apex of the Eiffel tower. Can you deduce from that the shape of the Eiffel tower? Obviously not... in the Afshar experiment every thing is the same.

This is clearly in disagreement with the conclusion of Afshar and is sufficient to refute all his reasoning.

--Drezet (30 may 2005)

Remarks concerning Unruh's reasoning

In august 2004 the well known physicist Unruh (see [7]) proposed a simple counter argument (i.e. a gedanken experiment) in order to reveal the mistake in the reasoning of S. Afshar. The gedanken experiment of Unruh uses a Mach-Zehnder version of the original set up build by Afshar and seems to be in appearance an elegant alternative to the experiment described in [8]. However in spite of its interest it can be finally observed that the reasoning of Unruh missed the essential point of the argumentation. In order to prove that we will analyse briefly Unruh's proposal.

The experiment starts with the splitting of a initial photon wave packet into two by a half silvered mirror. The two wave packet 1 and 2 are then redirected on a second beam splitter and separated into the beams 3 and 4. Finally using two mirrors and a last beam splitter we obtain the two beams 5 and 6 (corresponding to the two spots A' and B' in Afshar's set up). Unruh observed correctly that his set up is for the essential equivalent to the one build by Afshar. He remarked in particular that if no absorbing device is introduced in the interferometer then the photon will never follow the path 4. This is clearly equivalent to the existence of fringes in front of Afshar's lens. After crossing the last beam splitter the photon has a probability of 50% to be detected in 5 or 6. However, and this is fundamental, nobody can tell us with this set up from which path 1 or 2 comes the photon detected in 5 or 6. We can be tempted to close one of the two paths 1 or 2 in order to see effectively the path followed by the photon. If we do that we always record the photon in 5 if 2 is blocked and in 6 if 1 is blocked. Additionally the photon has the same probability to be in the arm 3 an 4 which means no interference. This is clearly the equivalent of the single slit experiment (i.e. a single path experiment).

Nevertheless by closing one of the two paths we have different physical situations. It is indeed evident that we can not reproduce the interference observed in 4 and 3 simply by adding the results observed in the two single path experiments. This is the reason why in the double path experiment of Unruh nobody can tell from which path 1 or 2 comes a photon detected in 5 or 6. It is then not true to tell that the photon observed in 5 (respectively 6) has a probability of 100% of coming from 1 (respectively 2) since nobody can test this fact experimentally without strongly disturbing the system. The same conclusion is valid with the lens. We observed two spots A' and B' but we don’t know if the photon detected comes from A or B: This is a metaphysical question for a quantum physicist. What we can deduce from the observation in 5 and 6 or in A' and B' is the number of photons coming from 1 and 2 but this is only a statistical result which should not be confused with the concept of which path information.

Now Unruh add a beam block in the arm 4. In the double path experiment this changes nothing because no waves propagate in this arm. This is clearly the same conclusion that the one obtained with the wires in the focal plane of the lens. However in the single path experiments the results are different since the beam going through 4 is blocked: the photon has now an equal chance to be recorded in 5 or 6. Unruh deduced from that that in the double path set up a photon detected in 5 or 6 has a probability of 50% of coming from 1 or 2. He then concludes that the experiment of Afshar doesn't conserve which path path information. However as analyzed previously the concept of which path information is dangerous and fallacious in quantum mechanics. Indeed by adding again the statistical prediction of the the two single path experiments (i.e. by adding the number of particle observed )we can not create the 'fringes' present in 3 and 4. It is then wrong to tell that in the double path experiment with absorber in 4 the photon detected in 5 or 6 has an equal chance to come from 1 and 2. In reality nobody knows it and nobody can really test such assumption without changing dramatically the experimental situations.

It can be added that the experiment of Afshar differs from the one proposed by Unruh on one point: if we introduce the wires in the single slit experiment the probability for the photon to be scattered or absorbed is only of few percents. This is far from the 50% of Unruh and this proves again that the essential point is not the hypothetical dualism between which path and interference but the complementarity between the observation in the focal plane and the image plane (Afshar's experiment). It can be observed finally that in Unruh's double paths experiment with absorber in 4 we can simultaneously measure the number of photon in 5 an 6 and be sure that no photon goes through the arm 4 (in the other case the absorber should count some photons). On this point the conclusion is different regarding Unruh's or Afshar's experiment since we explained previously that in the Afshar experiment the complete knowlege of the fringes and of the images can not be obtained with the same particles. The present discussion is not however in contradiction with our analysis of Afshar's experiment. Indeed in the experiment of Afshar the numbers of photons in the focal and image plane are associated with two non commutative observable (momentum and position) which are consequently complementary. It is then forbidden to build up simultaneously (i.e. by using the same particles) the two statistics in the two planes. But such constraint doesn't exist in the experiment of Unruh since the observation in 5 and 6 are not complementary of the observation in 4 and 3. Unruh's experiment is then not a test of complementarity and can not be compared to the experiment of Afshar.

Since I respect the scientific work of Bill Unruh I Hope that he will not consider my argumentation like an agression (PS: I agree with him that the argument of Danko Georgiev is a non-argument : with the same kind of non-argument it will be soon possible to prove that Mickey mouse is a cat and that Schrödinger is Mickey mouse. )

I would like to add that I made at the beginning (july 2004) the same mistake that Unruh did. My argument was the following : With the wires present we observe that the signal in A' with only A open is modeified when we open both A and B . This prove that something coming from B is going in A'. and then this should erase the which path . But in reality the changment is only of few percents and of 50 %. This prove that I was wrong (like Unruh). Now my argumentation is different as described before.

--Drezet (30 May 2005 few seconds later)

Remarks concerning remark concerning Unruh's reasoning

Latest comment: 20 years ago4 comments2 people in discussion

OK - please note that Wikipedia's ambitions have to be limited, to providing a good survey, in any scientific controversy. We cannot here try to establish truths, or make arguments, that are in advance of quite well-established scientific literature, i.e. the published papers (or at least easily accessible pre-publications, of good reputation). This is not a forum for cutting-edge physics; the standards of survey articles are the appropriate ones. Charles Matthews 15:40, 30 May 2005 (UTC)Reply

reply: since the work of Afshar didn't respect the rules mentioned by you here I dont see why you object me to do the same. My reaction is natural: I'm a professional physicist and I always submit my work to reviewed journal. Since the work of afshar doesnt obviously respect the good order: 1) review article 2) popular article and web forum I decided to react against Afshar's way of acting. Naturally if his work will be published (perhaps in Mickey mouse journal) I will comment officially. regards --Drezet (30 May 2005 one minute later)

Wikipedia policy on 'original research' is quite strict. And we certainly never accept arguments of the type 'if X breaks your policy, so can I'. Never. Charles Matthews 16:07, 30 May 2005 (UTC)Reply

Also please see my comments above. There are several problems with this point counterpoint approach in Wikipedia which are clearly illustrated by this article.

• The "referees" (in this case, you, Motl, Unruh and others) are immediately subject to a critique by the author submitting the work. This allows the author an unusual advantage in the review process. Imagine submitting a paper to a journal where it can never get rejected, but in which reviewers comment's are always subject to public review by the author. Now journals do allow for further review of an editorial ruling, sometimes, but this review process terminates.

• This particular author has used legal threats against one "reviewer" (Motl). These legal threats were completely unrelated to utterly childish behavior on th epart of Motl, and in any case are against WP policy.

• I have tried to edit the article using only widely known facts about Afshar, his experiment, the formal statement of the principle of complementarity using consistent histories and the onlinecritiques. I have not concluded anything other than (1) his work has not been published in a peer-reviewed journal (2) His work is regarded with skepticism.

• The final leap of reasoning that the formal statement using consistent histories does not appear to be proven, is not my problem or anybody else's problem on WP at least and I refuse to be put in the position of having to prove Afshar is wrong. The burden is on him to get his paper peer-reviewed. --CSTAR 16:35, 30 May 2005 (UTC)Reply

Dear CSTAR and Charles Matthews, Thank you for your comments . Since you are probably the most adult persons on this page I can only say that I feel guilty to play the same game that Afshar. But this is the risk on this free web page (the philosophy of a Blog is very dangerous by definition since effectivellly there is no reviewer). I Will not include anymore comments concerning Afshar's work but you should try to understand my reaction: Imagine you are a physicist interested in quantum mechanics like me. You try to solve all quantum paradox just in order to clarify your thought. Due to the fact that you are like me very pretentious you are totally convinced that Bohr is not the end of physics and that Einstein will be back (no like the christ i hope).

After that one morning you drink a good coffee made with pure colombian powder... and now you open new scientist july 24 2004 you see the title of Afshar article and then you have suddenly 2 reactions: 1) you laugh like crazy and 2) you become furious because this work is in certain cense published and that this is non sense and go against any basic idea od objectivity and science.

what should you do if like me you believe that science is and must be a place for logic and rationality?

Ok now I am still waiting for any review of Afshar's work even if a realize that this is less probable that to find one day that the moon is made of green cheese.

Finally there is a problem with reviewed article: sometime there are wrong because the reviewer was mistaken and some other physicist will publish some replies later. The process is more objectif that here but the difference is only quantitative not qualitative . So dont be furious if i included my comment to Afshar's work here. If you dont like my way of thinking /acting supress my comment but then eliminate the page of Afshar too.

with best regards and no agressivity

Aurelien Drezet ,Graz --Drezet (30 May 2005 few minutes and one coffee later)

Few scientists have not had to deal with the unpleasant experience of journal rejection (maybe with the exception of Witten). The outcome in that case is rewrite and resubmit or ask for independent advice or perhaps desist and submit to the arXiv and leave it at that.--CSTAR 17:52, 30 May 2005 (UTC)Reply

You are completely right (even if I am not sure that even Witten was never rejected: But I am sure That Isaac Newton was not rejected) and I dont understand why the work of Afshar is not on the arxiv (los Alamos). Perhaps he should ask some body to rewrite his paper with him (I say that not for the english of Afshar which is better than mine but ffor the very non usual style) and to submit it to an other journal less important (a paper is a paper after all : if you can add it to your CV it is good for you). I still don't understand why he submitted his work to PRL (why not to Nature or the Times? like Einstein). Since the article is very controversial he should submit it to something like foundation of physics. But OK this is not my problem (who I am after all to give advices of that kind?) since I believe (honestly I should say: I know ) that Afshar's work is scientifically unbelievable.

stay in peace and keep cool --Drezet

Interference of crossed beams !!!

Latest comment: 20 years ago2 comments1 person in discussion

Dear Aurelien,

WHY YOU ARE SO BLIND? Take A CAREFUL LOOK OF YOU PICTURE THAT SHOWS HOW THE IMAGE IS PRODUCED - THERE IS CROSSING OF THE BEAMS THAT PRODUCE THE IMAGES A' AND B'. [Since the angle theta is close to zero the mixing of the two channels can be considered complete, see the formula below, in Afshar's setup the distance to lens is 4.2 m, while the distance between the pinholes is JUST 2 mm i.e. theta -> zero]. If you really are "physicist" as you call yourself then you should KNOW that:

"Cross term of crossed beams is proportinal to 2 cos(kx.sin_theta) where 2 x theta is the angle between the crossed beams". In Afshar's experiment the production of the image is result of crossed beams, so there IS INTERFERENCE even IF there is no GRID before the lens.

Please just take a look of the lecture of Rick Trebino:

Rick Trebino (2003) Lecture 18. Coherence and Interference

http://www.physics.gatech.edu/gcuo/UltrafastOptics/3803/OpticsI18CoherenceInterference.ppt

In order to see who is Rick Trebino check:

http://www.physics.gatech.edu/people/faculty/rtrebino.html

And it seems that you need to read a full course in optics:

http://www.physics.gatech.edu/gcuo/UltrafastOptics/index.html

Best,

dear Danko just one word to express my feeling HAHAHAHAHAHOUHOUHOUHI!!!!! ARG arg it is so good to laugh

Your are very comical but as usual you are 1) nervous and 2) wrong. I am no blind (but probably i will become blind soon if I continue to read such comments) and clearly you are not physicist (but you are however comical as I told you before). Perhaps I was too fast for you and I regreat it. I am unfortunatelly for you a specialist of optics so your no-comments are really inapropriate. I see that you know what is a fringe ...great: I am happy for you . But this is not sufficient to understand quantum mechanics and complementarity.So now you shoud do the second step after the re-discovery of interference you should rediscover the photon.

alea jacta est

--Drezet

Dear Drezet,

first of all your commentary is ridiculous. You call yourself "specialist in optics", but I don't feel you understand the basics of optics. This is evident even from your picture of Afshar's experiment.

• First of all the grid is before the lens, and not after the lens. IF the grid is after the lens there will be great loss of photons because the interference fringes that exist before the lens, hardly will preswerve their size and shape after the converging action of the lens.
• Second, your picture is wrong because the distance from the double slit to the lens is 4.2 m and from the lens to the image plane the distance is 1.38 m. The proportions are clearly exactly the opposite of your drawing. [Not to speak that the distance between the two slits is just 0.002 m, so the angle theta is approaching zero].
• Third, simply you don't understand the meaning of the term interference, you don't have any deep understanding of the mathematical formalism of complementarity, so you cannot understand the predictive power of the usage of density matrices. Certainly the existence of Fourier transform between the lens focal planes is indicator for interference because without interference you CANNOT have Fourier transform.
• And last but not least, your 'laughing' suggests me that I should not even mention your name in my paper [because you are not scientist whose name deserves to be quoted at all!], and I will present your ideas as 'third person's possible opinion' and I will then make my coment on such wrong views.

Surely the readers of Wikipedia can do their own reading and decide whose ideas are right. The truth does not care about our human desires, and always survives the critique. So far noone has presented clear mathematical reply to my thesis, that is presented in un-ambiguous mathematical way.

p.s. I did not understood your laugh that concerns interference and fringes. My point was to OBVIOUSLY point out, that you cannot avoid INTEFFERENCE of crossed light beams, or CROSSED photon trajectories. Therefore you are the one who does not understand the quantum nature of the photon. :-)))

Best,

Danko Georgiev, MD

I'm a little puzzled by your reference to "Fourier transform"; particularly something like

Certainly the existence of Fourier transform between the lens focal planes is indicator for interference because without interference you CANNOT have Fourier transform.

Do you mean something like high-frequency asymptotics (as formalized by Fourier integral operators)? I fear I am joining the ranks of the blind here. --CSTAR 17:30, 31 May 2005 (UTC)Reply

HAhaha HIHI HOUHOU BETTER AND BETTER!! Dear Danko it will be really a pleasure for me if you can remove my name from your paper. Really it will be even better for my dignity of physicist and human to never see my name associated with yours. I have nothing against you but the discussion become senseless and if we continue like that we will become impolite.

Just a point a lens is definitivelly a good system to image and it is then a good sytem to realize one experiment like the delayed choice experiment of Wheeler. If you dont agree with me then you disagree with Wheeler and I guess with the the rest of the universe.

PS: Dear CSTAR let me help you for understanding the thought of Danko: I think that he tells us without fourier transform we have not fourier transform HAHAHAHA HIHI ARG ARG (life is fantastic) --Drezet

Dear CSTAR,

Your question is good one, because you seek for the link between the interference and Fourier transform. Well, the Fourier transform [let's denote it f(x) --> F(x)] transforms a function from time into frequency ___domain. This means that every point from one of the functions say f(x) is projected with some weight upon every point of F(x). Actually there is no one-to-one mapping between element of f(x) and element F(x), but there is holographic transform. Actually the Fourier transform is one of the basic things that you learn when you study the principles of holography. Steven Lehar (2003). An Intuitive Explanation of Fourier Theory http://cns-alumni.bu.edu/~slehar/fourier/fourier.html

But of course it is better if you read my paper [9] and how Fourier optics is linked to lens action. Also I provide example WHEN if there is no interference, the lens does not perform Fourier transform between its focal planes. All my results are backed up with detailed mathematics.

What about Drezet's laugh - it shows incompetence : I do not come to the tautology without fourier transform we have not fourier transform - Actually IF you don't have interference, you CANNOT implement Fourier transform, but the inverse is NOT TRUE - IF you don't implement Fourier transform, this does not mean that you cannot have interference. So, dear Drezet, you are on the wrong way again. You cannot even provide some clever joke, and you have scored auto-goal again :-)

Best,

Danko

Suppose you cut some interval of f(x) [say from -1 to +3]. What you will obtain is NOT F(x) with some cut in it, but you will get again F(x) varying from -oo to +oo, without gap in it. You may read this paper on holography

Well of course, this is just the fact that multiplication gets turned into convolution by Fourier transformation. --CSTAR 20:34, 31 May 2005 (UTC)Reply

Dear Danko after such explanation I can only correct my thought: Danko wanted in fact to say without interference there is no interference OUAH HAHA HIGGI HOOUUHOUHOU ARG ARG kauf kauf!! Ok now i stop joking with you. You was like Afshar a good entertainment but my job is to work on quantum and nano optics not to discuss about how many angels can sit on the point of a needle --Drezet

dear Danko , I realized that I could offend you (for this I apologize even if your not very polite too).

I can not give you an anwer for your questions since you missed to many important points (optics, quantum optics ,logic....). Then I have presently no other choice that to stop this senseless discussion with you.

I regreat that we discussed on this page with such agressive style and I apologize too to the creator of this interesting philosophical forum.

I forgot to say that I realized that you are not a professional physicist . This is not a problem for me and I was stupid to offend you since I am a professional physicist and I learned with time how to find a mistakein a reasonnig very quickly. You seem to be an autodidact and this is very courageous.

But like me you should learn how to be prudent and modest (perhaps I have more to do in this direction).

your argumentation copncerning Afshar is not good but I have no time to explain you again and again why. If you want we can discuss with private email ?

with best regards Aurelien Drezet

dr Aurelien Drezet, institut for experimental physik Graz Austria.

--Drezet

Interference of crossed beams (bis repetita)

I want to add a short scientific comment concerning Afshar's work :

Afshar not only claimed that he can circumvent Bohr’s complementarity but that he can effectively determine the path followed by the particle. Afshar, following here a assumption originally enounced by Bohr , Heisenberg and Wheeler, accepted that even with the two pinholes open a photon trajectory (if trajectory there is) will necessarily connect a pinhole to its optical image as it is if the other pinhole would be closed. However, as is was realized by numerous physicists as de Broglie, Bohm, Bell and Scully, this is a free metaphysical assumption which depends of our model of reality and which can not in general be experimentally tested [read for example “ Surrealistic Bohm trajectories”, Englert et al in Z. Naturforsch. Vol 47a , p 1175.].

Effectively nothing in the Afshar’s experiment forbids a photon coming from one pinhole to go in the ‘wrong’ detector for the second pinhole (this is the case for example in the Bohm’s theory). Looking the image of a pinhole recorded in a statistical way by a myriad of photon will not say us from which pinhole an individual photon come from but just how many photons crossed this pinhole (in reality it is even more terrible since quantum mechanics only tell us what will happen if we observe the photon). In counterpart of course we can not see the fringes and the complementarity principle of Bohr will be, as in every quantum experiment, naturally respected.

Since I am not a defender of Bohm' view I will not go further in this direction but you see that th concept of trajectory is ambiguous for a photon. --Drezet

Dear Aurelien,

I am glad that you start to see what I am saying - there is no which way information in the two pinhole case. The fact that there is lens changes nothing. If all those people including Wheeler et al. have ever claimed that the lens image contains the which way info at the image plane, then i will have to add them in the black list of the people who had done severe error.

By the way - as I know, Wheeler determines the which way with 2 telescopes = 2 lenses, not a single lens, and the 2 lenses do not cross the light beams. Do you see the difference?

Well, by for now, I will be back soon. Contact me by e-mail for further discussion.

Best,

Danko Georgiev, MD

Dear Danko just to tell you that I desagree Afshar's experiment is unlike the Schrodinger cat completely dead and it is useless to try a reanimation : you are not Frankenstein --Drezet

I noticed the "neutrality disputed" tag on the main Afshar page and wondered if I should remove my entry, "Kastner's Interpretation", on that page. If it is desired that I do this, please let me know, and I'll be happy to do so. May I still list a reference to my paper somewhere on the main Afshar page?

Thanks, R. Kastner

The POV banner has nothing to do with your entry. I put the POV banner up about a month ago, but the page now seems a little more balanced (although still could use some trimming in the pro/con section). Whatever happens to that section, my guess is that your reference (as well as Motl's and Unruh's) should probably remain, but of course, this being Wikipedia, who knows?--CSTAR 23:33, 17 Jun 2005 (UTC)

Dear Dr. Kastner, I have no qualms about moving your entry, as well as my response to it, to this discussion page until we work out our differnces through e-mail and my weblog. But since I have been accused of being biased in the past, I cannot do it. Perhaps you and CSTAR could sort that out? Best regards.--Prof. Afshar 11:41, 18 Jun 2005 (UTC)

Proposed deletion

There's too much of XYZ's objections and Afshar responses. I think they should be deleted and replaced with references to blogs and other websites. However, I also think it is fair to add the statement the preponderance of scientific opinion is that Afshar's experiment does not refute complementarity. I don't like use of "opinion" here but I can't think of a better word that would conform to NPOV policy. --CSTAR 16:45, 21 Jun 2005 (UTC)

I'd certainly support that. As it is, the article is more personal-bloggish than encyclopedic. -- Reuben 18:38, 21 Jun 2005 (UTC)

I support that with 100 % and even if iam sad that my proper last comment will desapear (sob! sob!) I think that the mention :the preponderance of scientific opinion is that Afshar's experiment does not refute complementarity is extremely good (even if I dont know personally any physicist which is pro-Afshar ). --Drezet

I recently gave a talk at a physics conference in Vaxjo University in Sweden, where the majority (30+ physicists) agreed with my conclusion that the common reading of Bohr's Complementarity principle (based on the current literature) is ruled out. Some initial objections were replaced by acceptance of my conclusion upon further discussion after the talk. So I certainly disagree with the sentence the preponderance of scientific opinion is that Afshar's experiment does not refute complementarity. That is the opinion of a few vociferous opponents, not the scientific community. Also, the paper has been accepted for publication in Proc. SPIE 5866, 229-244 (July 2005): http://bookstore.spie.org/index.cfm?fuseaction=DetailVolume&productid=604724 . This and other publications in the works, as well as the growing list of supporters of the work (see my earlier entries for a partial list) reflect the fact that although my experiment/conclusion is controversial, it is aptly viewed by the major practitioners of the field as a revealing and relevant one vis-a-vis the discourse on the foundations of QM. As mentioned before, any claims regarding "the preponderance of scientific opinion" without a scientific polling of the experts in the field would be baseless and irresponsible. At this point the majority seem to be agnostic rather than antagonistic. I suggest all those who have made their opposition publicly available to attend my talk at the upcoming SPIE meeting in San Diego, where I would have the opportunity to address their comments in person. Simply put, the fat lady has not song yet despite the opinions of some. Nonetheless, replacing the long Contoversy section with web links is a good idea. You may also wish to include the Proc. SPIE ref. for the paper which also includes further suggested experiments.--Afshar 01:11, 22 Jun 2005 (UTC)

Reply to Afshar: You will note that I have tried to keep my personal opinion regarding your interpretation of the experiment out of this discussion. I have tried to base my edits and comments clearly on what others have stated. However, I think your claim that this is the opinion of a few vociferous opponents is a bit disingenuous. Moreover I was the one that made the comment earlier in this discussion that

A few words in the introduction bother me, particularly "many physicists" are skeptical which I believe should be "most physicists" are skeptical. However, I have not conducted a scientific poll, and I am sure that fact would be brought to my attention.

Indeed, you just did bring it to my attention as I expected. However, I do not regard this as you do as being baseless and irresponsible. Your evidence in support of this last assertion is purely anecdotal. In any case I suggest that we wait for more comments from other interested parties on this page. If worse comes to worse I will request deletion of the entire page.--CSTAR 20:55, 21 Jun 2005 (UTC)