Talk:Afshar experiment/Archive 6

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The Question is WHY?

Dear Carl, thanks for your reply. You ask WHY Afshar makes the error. I have already provided the answer WHY [1]. I have shown that wave functions CANNOT be distinguished ONLY by having a probability distribution at a single plane, no matter whether it is image plane, or any other plane. The probability distribution function is defined in 4D [I speak about the probability distribution function which changes in time!] so knowing the probability in just a single 2D plane does not give you the spatial 3D behavior of this function [neither gives you the temporal behavior]. TYPICAL EXAMPLE is Afshar - he sees two well formed pinhole images and like little child say "here it is the which way info". The WHY of your question, is answered by BECAUSE Afshar is ignorant in basic math principles. Alas, this is common feature to others as well like Aurelien Drezet, that connects the image plane with which way info, and Fourier plane with no which way info. I ALREADY HAVE SHOWN in my pdf quoted above that IF you have polarized photons the lens CANNOT provide REALLY full Fourier transform, but creates TWO INDEPENDENT FOURIER TRANSFORMS i.e. the typical mixed state. Actually Drezet is not the only one who makes this labeling of lens planes with names "which way one", "no which way one", "bla bla one". This even presented in Anton Zeilenger's papers, but what can I do. Nothing! This is WRONG math, based on WRONG clasical and popular misunderstandings, only math can open the eyes of these people, but they do not want to see it. In simple sentence - IF you want to SEE the probability distribution LOOK at the whole 3D space, otherwise you cannot make claims about what function you have [i.e. which way one, or no which way one - lens planes do not have which-way/no-which-way property, the probability distribution function has which-way/no-which-way property and it is described by the nature of the density matrix of the quantum state] Danko Georgiev MD 05:59, 25 January 2006 (UTC)

Addendum: This principle - LOOK in the whole 4D space [here I include also the time] explains the Q-non locality or backward causality, where the future in some sense causes the past - this is expressed also in the inseperable nature of the quantum coherent state. If one do not understand this quantum "wholeness" better find another hobby, not QM.

Hi Danko, I don't know why you need to keep SHOUTING. I understand what you are saying. Believe me. But how about listening for a change?

One of the things Afshar is doing (although he may not agree) is using quantum theory to question Bohr's interpretive concession to classical theory.

There is no which way information in Afshar's experiment. But then there is no such thing in Bohr's theoretical outlook either. Both Afshar and Bohr use the words "which way" to represent a concept that exists in the imagination of classical thought. That doesn't mean it's not useful or interesting.

The danger here is that both Bohr and Afshar risk being misinterpreted as positing the validity of the which way concept. Afshar misreads Bohr. You and I misread Afshar.

You might think that this is all just "blah blah" and nothing to do with QM but you will be wrong. Have you read Heisenberg's talk on the philosophical background to quantum theory? Do you think that matrix mechanics just fell out of the sky to be forever SHOUTED at people?

Afshar's experiment is a reasonable one. The wires provide a demonstration of how the interference of the wavelets from each pinhole can be inferred without actually recording any interference patterns! I don't know why Afshar says they are "visible" but lets just say he means "inferentially visible".

Now whether or not the "which way" information is "there" depends on whether you choose to look back at the pin holes through both detectors or just one.

This has nothing to do with the wave function. The wave function's interference, either side of the lens, is not expressed in the detector data as the detectors are beyond the reach of any possible interference patterns being recorded. And as you say, the detectors are just 2D so the fourier components are not expressed. And by the way, this throws water on my hologram experiment since such would have been exposed in Afshar's detector data - as interference patterns. (addendum - good grief, what am I saying? There would be no interference patterns in Afshar's data for that very reason!)

But in Afshar's experiment there are pinholes (as distinct from mine) and there is no (visible) hologram in his detector data (nor in mine). The wave function (on the other hand) can be assumed to still possesses it's coherency and a simple but different experiment would demonstrate this. But in Afshar's experiment this is is not expressed.

Now there are two things here.

One is that the interference of the wave function (where the wires are) is inferred, ie. not actually recorded. This is okay. It's clever and it's interesting. But we need to be careful because concessions to classical theory are only possible if the wave function can remain (if only in the imagination of the classical mind) an approximation of where a particle is. In Afshar's experiment, the wave function is demonstrated ex situ.

Ok. On the which way side, where the concession is normally possible, eg. using a single pinhole, it is no longer possible. The which way concept was always an inferred reality, but now it's not possible unless we counter that the equally inferred wave function is somehow disfunctional. But how? It's clever.

Which way information is being annihilated!

And yet strangely, we can restore complementarity at that point where it looked already restored by the annihilation of which way information (if only in virtual reality) by showing how the decision regarding how we infer the pinholes - using one or both detectors, is in actuality, played out.

This leads us back to how we might re-express the pinhole distinguishability criteria. And fortanatly, where some mathematics can be reintroduced. And the principle of complimentarity, albeit enlarged.

That's for another day.

Remember, a rose by any other name smells just as sweet.

Carl

Dear Carl, I am not shouting, I could underline the main point in bold, but you can also misinterprete it like shouting.

Afshar may have disproved some interpretational aspect of Bohr, and even may have quoations proving his thesis. I have said only that Afshar must know that modern complementarity has strict math definition, so complementarity is no more in the scope of popular science. The fact that Afshar cannot understand my argument based on simple writing of density matrices for me is evidence that Afshar's knowledge in physics is quite limited and I feel sorrow for his 18 years of studying. If I have studied for that long physics possibly I would have moved in some advanced topic in brane theory, not try to do "fishing for red herring". Danko Georgiev MD 11:18, 25 January 2006 (UTC)

What about Heisenberg's principle?

Dear Carl, although I do not want to convince you that Afshar's error is not just interpretation, but very deep math problem, I will just note by the way that usually complementarity is linked to non-commutable variables, and Heisenberg's principle. So why Afshar never stated that he has disproved Heisenberg's principle as well. Here is the quotation from the wiki article:

"The principle of complementarity states that two complementary physical observables cannot both be measured for any given quantum particle. For example, a particle's position and momentum cannot be observed at the same time: this is Werner Heisenberg's uncertainty principle."

Well, I suspect that after Afshar gets the Nobel prize for disproving Bohr, he will apply for second Nobel prize disproving Heisenberg. He possibly does not want to shoot everything at once. Danko Georgiev MD 11:26, 25 January 2006 (UTC)

---

Dear Danko, my apologies for getting a little defensive. Neither complimentarity nor the uncertainty principle is compromised in Afshar's experiment. For one thing there is no visible interference pattern (physical observable). So if we are to be mathematically and conceptually strict, Afshar is already wrong here. The wave function of quantum theory, with it's due concession to classical theory (ala Copenhagen) is a mathematical model for predicting actual interference patterns. Since no such patterns are there to be predicted, and the wires are invisible to such predictors, one should question what is being demonstrated here. Are we to say that the experiment establishes the wave function as a reality? From a neoclassical point of view - yes. But from a quantum theoretical point of view - no. Quantum theory was developed in response to very strange but very real facts: the measurement of actual particles (not virtual which way ones) and the actual interference patterns they made - not the virtual interference patterns we might use to predict (compute) such patterns.

(addendum)

So since there are no *visible* interference patterns, the visibility of such equals zero. V=0. That is all that's required to knock down the math.

But I like the experiment. It's conceptually interesting. I like what EPR tried to do. And I like Bohr's comeback even more. I like Bell's inequality tests. I like Cramers approach.

Carl

Dear Carl, there is clear interference in Afshar's setup, and I do not understand what changed your mind. There is so-called Reininger negative measurement experiment in which you collapse the wavefunction WHEN you DO NOT observe the particle. So the Afshar's experiment is no which way from the beginning to the end. At the pinholes you have coherence, so you have interference, at the wires you detect ZERO intensity, so you make negative no which way measurement [Reininger!] so you have again interference, and finally at the detectors the photon comes in superposed pure state ${\frac {1}{\sqrt {2}}}(|D_{1}>+|D_{2}>)$ , where the photon is both detectors. There is so-called measurement postulate that says IF you measure a superposed state, you irreversibly collapse it to one of the basis states in which the measurement is done. So now if you read the argument in my pdf explaining the measurement postulate - you cannot make difference by measuring a pure state ${\frac {1}{\sqrt {2}}}(|D_{1}>+|D_{2}>)$ in basis $|D_{1}>$ , $|D_{2}>$ , and measuring a mixed state ${\frac {1}{2}}|D_{1}><D_{1}|+{\frac {1}{2}}|D_{2}><D_{2}|$ in basis $|D_{1}>$ , $|D_{2}>$ , . In both cases you obtain ${\frac {1}{2}}$ at $D_{1}$ and ${\frac {1}{2}}$ at $D_{2}$ . of course you have to use and you can use other types of measurements to distinguish between pure state and mixed state. For example you can NOT measure/detect two photons at the detectors, but you can catch them in an optical fibre. Then after clever arrangement you can let two such captured photons to interfere. If the two photons catched at the detectors are in pure state ${\frac {1}{\sqrt {2}}}(|D_{1}>+|D_{2}>)$ they WILL INTERFERE, because they are coherent. If the catched photons are in mixed state then they will NOT INTERFERE becuase they are not coherent. Please read my pdf at least very very fast looking over the topics, there I present a dozen of proposed alternative methods to test Afshar's claims. I feel that you start to be confused, while I am still absolutely sure in my thesis, because it is based on unshakable mathematical fundament - the difference between mixed state versus pure quantum state. p.s. Please ignore Afshar's comments. He has never heard of interference of quantum momenta and just shows his ignorance in the topic. Danko Georgiev MD 07:50, 26 January 2006 (UTC)

Dear Danko and Afshar, this, it would seem, must be my last word here in Wikipedia. Since Danko has been excluded from the discussion at the weblog it must be my last word (with Danko) at the weblog as well. And Danko, yes, there is an error in my reversal re. the hologram experiment. The fourier plane in Afshar's detector would not be able to distinguish between a real pinhole and a hologram of one. The interference of the wave functions (from the hologram) vs the non interference (from the real pinhole) would be indistinguishable in the detector data - for the reasons discussed. My error.

-- NB. I make a distinction between 'interference' in the quantum theoretical waves and actual "interference patterns" in the data. The later is physical data, the former is not. I try to keep this distinction running through my discourse but I sometimes slip, on the assumption that this distinction remains understood. But I risk misrepresenting one as the other. To myself as much as anyone else. So while coherency can be quantum theoretically sustained in the fourier plane of Afshar's experiment - this is a different thing from actual interference patterns ie. the data. So when I say there is no interference patterns in Afshar's experiment I am only referring to the data - not the quantum theoretical state. I want to continue this discussion with you ... otherwise, thanks for all the fish! Very much appreciated.

Dear Carl, I am glad that you have seen your error. Actually your hologram experiment idea was very good one, and after that you were in temporary delusion. Now I see that you have found the right track again. What about the Afshar's blog - I AM NOT BANNED! I could post on the blog from almost any I.P. address that I want, and Afshar cannot do anything to prevent this. However it is my personal will not to post on Afshar's blog. I do not offend Afshar directly as he does offend me because my academic position in the University and my status of medical doctor do not permit me to behave like that. From Afshar I have heard to be crackpot, having brain disorder, etc. .. If you check below his reply you will see that he does not understand momentum in QM, but I will not be his teacher. If you [Carl] want to discuss something with me, check my Wikipedia information for contact. I am quiting this endless discussion. Danko Georgiev MD 04:08, 27 January 2006 (UTC)

Hi Danko, my email to you bounced so here it is for public scrutiny.

Bohr would say (if I can be so bold), that in Afshar's experiment, one should not misrepresent the meaning of V, eg. using a value close to one. On the contrary one should represent the meaning of V with a value close to zero.

This is somewhat contrary to what a neoclassical theorist might do. But it's what a quantum theorist would/should do. The reason rests on the very important distinction one should make between the quantum theoretical wave function and the information/data rendered in actual experiments. The data is real. The wave function is not.

V represents, or should represent, what is otherwise rendered in the data.

V should not be used to represent some attribute of the quantum theoretical wave function. The reason for this is not mathematical per se but deeply philosophical.

It is a misrepresentation of Bohr's philosophical position (and therefore quantum theory) to say that Bohr erroneously applys destructive measurement schemes. Bohr does no such thing. It is precisely the data that results from so called "destructive measurement schemes" that defines what is being theorised in quantum theory.

But lets not get too hung up here. If V is defined neoclassically then the problem goes away. Bohr can go back to sleep. And so can I.

Carl

E, t uncertainty violation

Dear Carl, I will only repeat that V=1, because all the light intensity passes through the wire grid. You detect with the wires ZERO intensity, so you prove that there is quantum interference. Afshar uses wires that diffract the light around, but you can use silver compund detectors, so they absorb all the light. In the which way scenario, you will absorb with these wire-silver-detectors 6% of the applied light, and this is analogous to case when you have polarization filters on the pinholes. In Afshar's case the putative silver-wire-detectors will absorb ZERO light AS IF they are inside an absolutely dark room. This is so becuase they are in the interference minima, and there is really DARK !!! You make Reininger negative measurement and you collapse the wavefunction in Energy basis, because you precisely measure the photon's wavelength [energy]. K however is ZERO, because you do not have which way info. In view of the E, t Heisenberg uncertainty, you do not know the time needed for arrival of the photon at say detector 1, so you do not know whether it passed through pinhole 1 or pinhole 2 [the distance passed is different, photon's velocity is c]. So you have no which way info, and K=0. If Afshar was right, you can measure both wavelength $\lambda$ by knowing the place of interference minima, and the photon's energy $E={\frac {hc}{\lambda }}$ . Then knowing the "which way" as Afshar WRONGLY suggests, by knowing the 5.2 m distance to the image plane, and the photon's which way path, you can simply compute the time arrival, and hence have precize measurement of E and t, VIOLATING WRONGLY HEISENBERG'S PRINCIPLE. No which way, as I said many times, so K=0, and V=1. E, t, uncertainty is simple because you work with scalars !!!! To work with p, x uncertainty is dangerous, because you work with vectors, and momentum IS NOT the classical vector any more. If you know momentum's magnitude [vector length] then you do not know its direction. So dear Carl, I would like to quit this discussion, and please contact me by e-mail. Although you are flip-floping your decisions, I believe that you may benefit from my mini-lectures. Danko Georgiev MD 10:48, 27 January 2006 (UTC)

Precisely. If we redefine V neoclassically, as you have done, then V=1. The wave function is no longer just a mathematical representation of what might be realised in a measurement (ala Copenhagen) but a neoclassical reality in itself. Within this neoclassical reality the concept of waves on the one hand and particles on the other are in direct mathematical/geometrical conflict with each other. Thus the apparent violation of complimentarity, and by mathematical ellaboration, uncertainty etc. They can only be brought back into "peace" with each other back out in the real world ie. where measurements are actually realised. For example, introducing polarisers, or downstream reinterference of the photons. This is more or less the same sort of strategy Bohr did with EPR. But in EPR the measurements are made *before* being brought back together. But it doesn't matter. The so called measurement problem takes place in virtual reality. It is the data which determines whether we jettison the probability function - not the other way around. I mean, I can still use a probability function to determine the probability of where I might find the trace of a particle in an already recorded interference pattern. I look at the pattern as a whole and zoom in upon the predicted peaks in the data - and viola - a single trace.

If we are to find a balance between the traditional virtual reality of classical thought, and the actual reality (ie. actual measurements) that traditional quantum theory theorises we must recognise that these two "realitys" do not occupy the same space. They face each other. Classical reality is that virtual reality inferred from measurements. The reality of quantum theory are the measurements themselves. Qunatum theory itself is not a reality. But in classical thought (and neoclassical thought) theorys are "realitys" in themselves. Measurements are not regarded as realitys in themselves - they are regarded more like pictures or "side effects" of some otherwise invisible reality. So in neoclassicism, an actual interference pattern would be just a picture or side effect of some "real" quantum wave function. Or, in Afshar's experiment, the small increase in the measured detector intensity would be a side effect of some real wave function.

If we adopt a neoclassical perspective then we will need to rewrite quantum theory from such a perspective. And that is something to do, certainly. In fact, it was just such an exercise I was hinting at when looking back at the pinholes from one detector or both, ie. complimentarity from a neoclassical perspective.

This can be called flip flopping. Indeed, we could use the term "flip flopping" as a technical term for a new expanded neoclassical principle of complimentarity.

We can begin with the Danko formula:

  Afshar does not contradict quantum principles because Afshar contradicts quantum principles.

[NO! This is senseless rumbling. My formula is (i) quantum principles and mathematics is consistent, (ii) Afshar derives some form of inconsistency, (iii) therefore Afshar MADE ERROR in applying the quantum principles and mathematics, (iv) I have tried to show clearly where his mathematical ignorance is. My claim has nothing to do with the above mis-understanding of Carl Looper. Danko Georgiev MD 04:12, 7 February 2006 (UTC)]

This can be mathematicaly expressed as:

  if V=1, then K must be zero.

And indeed, it is true. Were we to reinterfere photons from both detectors, we would discover that K = 0.

And if we didn't? Then K is somehat undefined. We can set it to 1, as Afshar does and use traditional quantum theory:

  Since V=0 and K is undefined ( or classically 1), then where is the pending cataclysmic upheaval in quantum theory?

But if traditional quantum theory is unsatisfying, and new quantum theory (ala Danko) sounds somewhat circular then perhaps we should rethink the issue in complete neoclassical terms:

 If V=1 and K=1 then ?

Then what?

Someone needs to finish this sentence. Afshar lets Danko do it. We end up back at the Danko formula. Perhaps Afshar should answer this question - not Danko. Danko has done a very good job I think. He has really tried to beat this one, but the onus is not on Danko to finish this expression. It is on Afshar.

Carl.

Dear Carl, your entry above is non-sense. It disappointed me fully. As I said in every experiment there is MATHEMATICAL OBJECT that CORRECTLY describes what will happen, and this math object is called DENSITY MATRIX. You have two types of density matrices - pure state one, where $\rho =\rho ^{2}$ , and mixed state ones in which $\rho \neq \rho ^{2}$ . Whether you let interference, or not of the captured photons is not important. You are joking with misinterpretations of my thesis. I DO NOT insist on your imagined wrong co-existence of quantum and classical ontologies. WHAT IS IMPORTANT for me is the NATURE of the DENSITY MATRIX. If you know it, you can predict not only the current experiment, but all possible experiments that you might have done, but you haven't done. This is called COUNTERFACTUAL DEFITENESS. My philosophical position is to think of the mathematical objects of ontologies, and not to try to substitute them with popular interpretation. (I am not into popular interpretations - Carl) In 2002 when I was studying QM basics I saw one very poor from my view interpretation, which now is my leading philosophical position - it is called "shut-up-and-calculate interpretation of QM" (this is a principle for children - Carl)In case of QM it is impossible to substitute the math objects with popular wording (true - Carl) and if you forget about the existence of density matrices, you cannot explain every experiment just by popular principles (true - carl), just because the popular wording does not possess the property of the density matrix, say $\rho =\rho ^{2}$ in pure state. Can you interpret that in popular wording??? (No - but you can derive it philosophically - Carl) Now i understand that you suggested the holographic experiment blindly, without understanding the link with the underlying density matrices of photons. Please repair that, before you introduce personal targeted irony in your posts. Danko Georgiev MD 04:25, 30 January 2006 (UTC)

Dear Danko - I am not at all a proponent of popular wording but I am a proponent of philosophical understanding - and irony is a part of that (it is an ancient philosophical technique). I am opposed to the "shut up and calculate" principle as it simply reinforces whatever the current paradigm happens to be. Imagine if Einstein followed that principle - would he have theorised relativity? No - he'd still be calculating Newtonian mechanics. Quantum theory has it's basis in a radical empericism. The wave function is a rationalisation of emperical data. From a strictly emperical point of view only the emperical data is real. The rationalisation is a representation of the data. The wave function represents the data. It is therefore an *effect* of the data - not the *cause* of the data. Now I understand holographic principles intimately. I write computer software for synthesising holograms from 3D models of medical data. I use wave functions every day. I agree with your position regarding "which way" being absent in Afshar's experiment. Until the wave function "collapses" the particle does not yet possess any emperical reality, ie. there is no data that we might call a "particle" - there is not yet what Bohr called "phenomenon". There is no measurement. But I disagree with the visibility of the wave function (through so called "negative measurement"). The wave function itself is not visible. It is not emperically real. It is, however, a mathematical object. So it can be allowed a kind of theoretical "reality". As I said, I use mathematical wave functions everyday to compute interference patterns. But that is all they are - purely mathematical - not physical data.

Reply to Looper - Negative measurement does not measure q-amplitudes!

Dear Looper, your explanation above is certainly messed, because you misunderstood the meaning of negative measurement. I have NEVER said that I observe the quantum amplitude [q-wave in popular sense] I have ALWAYS said that what you measure is probability distribution. I do not observe at the wires zero quantum amplitude, I observe zero light intensity, which is zero photons [real probability distribution]. But when you observe zero light intensity, you actually measure the photon's wavelength and energy, so you know that all photons that pass nearby but you do not catch with your wire detector have pricesely determined energy. So it is as if you have measured all the photons, so all photons at that point are measured/collapsed in basis energy. Now, since at the wires you make measurement in basis energy, so you get the result of the photons wavelength $\lambda$ but you have not measured in basis time [which is non-commuting with energy], so the photon remains in superposition in basis time! i.e. each photon has passed through both pinholes. At the detectors the photons come already in collapsed energy basis - that is you know its energy - but since you do not know the length of its time travel each photon is at both detectors. The subsequent collapse of the photon at one of the detectors does not tell you through which pinhole the photon has passed, so the probability distribution of photons [light intensity] is such of "no which way" measurement i.e. the photon arrives in coherent state at the detectors. Since at the wires you have "no which way" measurement and at the detecors you have "no which way" measurement then you make twice "no which way" measurement - so no problem. The fact that after you collapse the photon at one of the detectors and you know at which detector the photon now is, does not extract retrospectively the "time travel" - you know that the photon is at detecor X, but you do not know WHEN the photon arrived there! In this sense the second measurement is in "position basis" but again in "energy basis" - you collapse twice - you know the energy of the photon, and you know at which detector it is, but you do not know the photon's direction of momentum, so you do not know from which pinhole it came from, nor you know when it came there, thus actually it remains in superposition of time and direction of momentum. The measurement postulate says "If you make the same measurement sufficiently fast you will get the same result", so you measure in basis energy [at wires] and in basis position [at detectors], but twice you do not have measurements in basis time and momentum [its direction]. So twice you measure in NOT basis time. Afshar believes that there is conservation of momentum and quotes some wrong papers from early times when complementarity and QM was not settled on firm fundament. So he had the chance to show that the image plane is not necessary revealing which way information, but instead of this correct interpretation, he produced the pseudo-scientific "Afshar's interpretation" where he took the Nobel prize of Einstein. Danko Georgiev MD 04:49, 2 March 2006 (UTC)

Here I add a note why the second measurement should be considered again in energy basis? Well, the lens refracts photons with different wavelengths in different way, so there will be slight difference in the images of the pinholes created by say blue light, or red light. In Afshar's setup this effect might be "under cover" [i.e not obvious], but theoretically the second measurement at the detectors should be considered again as measurement in basis energy. Danko Georgiev MD 05:10, 2 March 2006 (UTC)

By-the-way: I whole branch in astrophysics [spectroscopy of stars] is based on the different refraction of light with different wavelength by lenses, prisms, etc. So dear Looper, double measurement in energy basis is giving you the same result. If you and Drezet understand this simple fact, you will see that there is nothing strange in negative Reininger experiment - knowing that something didn't happen is as real information as knowing that its negation has happened. So you may think negatively that you have detected zero light intensity, or think positively that you have measured 100% of the photons in basis energy [so you know now their wavelegnth!]. The same is similar to knowing that you are not happy, or that you are sad - two different ways to same the same fact. In negative measurement you measure probability distribution of photons [light intensity] you do NOT measure quantum amplitudes of photons !!! So at wires you measure energy, at the image plane you measure also energy - blue light will form two narrow peaks of the pinholes, while red light should produce wide peaks with less intensity of the maxima. Actually this is basics of microscopy - use shorther wavelength for better resolution of the image :-)))) Danko Georgiev MD 13:14, 2 March 2006 (UTC)

Apodized functions as CONSCIOUS FRAUD!

One more add to my detailed exposition above - I suggest where Afshar manipulated the data = conscious fraud?! Well, he used apodized functions to pass only the central maximum at the detectors (deleting the higher order Airy disc pattern!). As I said in case where you have which way info the maximum as the higher order Airy disc pattern will produce a picture different from the one where you measure the wavelength directly [like the no which way one]. If you see figure 8 of Afshar's preprint [2] the data of the first which way experiment have different intensity of the central maximum and the case when there are two pinholes open the central maximum is lower and the pinhole intensity seems spread wider. Of course if the higher order Airy disc pattern were there the two pictures would be too different, so Afshar's fraud wouldn't work. But Afshar cleverly removed this "bad result" by apodization. Now for non-experienced reader it may look like that fig 8a is like the fig 8c, but this is not so. If you had the whole picture considering as I explained above that in one of the cases you measure the wavelength precisely [no which way] you will have coherent light and monohromatic image, while in the case with which way info [i.e. one slit closed] you no more be sure of exact coherence of the light [regardless of the fact that it is emitted from laser] so you will have not exact monochromatic light, but wider spectrum of energies [superposition of wavelengths!]. I hope finally you can start to think seriously on the subject, a forget about "popular wordings". Please write down clear statements, not metaphysical rumbling. Danko Georgiev MD 13:47, 2 March 2006 (UTC)

There are a *range* of frequencys, each a harmonic of the wire frequency, that would predict the same "measurement" (data) in Afshar's experiment. Therefore, (to speak in classical rationalistic terms), the frequency of the light has not been measured (negatively or otherwise). We can allow that the frequency has been *partially* "measured", ie. that there are a range of wave function frequencys which would *not* yield Afshar's emperical results. By the way - good point about the airy disk. I thought of that too. Afshar keeps the aperture to a certain size, thus thwarting the production of relevant phenomenon (data) - but I don't agree it's fraud. Afshar is attempting, by whatever means possible, to yield an exception to the rule. He does not succeed (as far as I am concerned) but it is still a reasonable attempt - just like EPR is a reasonable attempt.

Carl

Dear Carl, you possibly may expect that I will disagree with you. Yes, and I think that the photons with with different frequencies might for example be adjusted to "pass" the wires with zero absorbtion, but then the different wavelength photons will be refracted in different way by the lens, so you will end up with different image at the detectors - consider my airy disc comment that you liked. So actually you are wrong, and in Afshar's setup is measured only on exact value of the photon's wavelength, which should be the announced in Afshar's preprint of 760 nm. Danko Georgiev MD 05:55, 3 March 2006 (UTC)

Yes, I must admit I was only thinking of the intensity drop (in the detector data), rather than the airy disk. So yes, good point again. But what if we did not have the the airy disk - ie, we only had a few particle detections to work with? Afshar's experiment is meant to be extendable (physically and conceptually) into single particle experiments. What becomes of V then?

Apodization (as any competent optical physicist knows) is a common technique used in optics and it has absolutely no bearing on loss of which-way information as emplyed in my experiment. One can alternatively use Gaussians slits, which ensures lack of extra diffraction bands, etc. I suggest to Danko to stop using the word "fraud" so liberally. It might land him in a court for libel, not to mention taint his academic record.-- Prof. Afshar 00:44, 3 March 2006 (UTC)

Dear Afshar, you still did not catch the main point. If you measure which way information you may have greater uncertainty in photon's wavelength, and if you do not measure the which way information, you will measure more precisely the wavelength by the place of the interference fringes. Since the Airy pattern is very sensitive to the wavelength of the photon, see wikipedia entry on airy disc then by deleting the airy disc pattern you ERASE the evidence that in the second case when you open both slits, the experiment has changed from "which way" into "no which way". I suppose you did not like the "little" differences that you possibly observed so you decided to apodize the images just for "fitting" your expectations. If you did not do that, then you have done error, because you overlooked the dependence of the Airy discs pattern on the photon's wavelength, so you cannot say that in both experiments the certainty of photon's wavelength is the same. So this is not just loophole, this is the loophole that unmakes your interpretation. Danko Georgiev MD 05:21, 3 March 2006 (UTC)

Danko, I agree with Prof Afshar about the making of accusations. Also, this WP talk page is not an appropriate forum to debate theory. I very strongly recommend that you find some other place to have these discussions. This all has been going on far far too long. linas 00:54, 3 March 2006 (UTC)

Dear linas, I don't understand what you dislike in the discussion. When Afshar called me "crackpot" you were possibly very pleased with the fact, but when I show evidence for "massage" of the experimental data, you do not like it. In every scientific field if there is "evidence for possible massage of experimental data" nobody cares whether you did it consciously or unconsciously - you are accused as fraud, and the only alternative way is to publically announce "I am not a fraud, but I have done severe error having overlooked the facts". In both cases the evidence goes against Afshar. Danko Georgiev MD 05:21, 3 March 2006 (UTC)

I agree with Linas and Prof. Afshar about this. What is the point in positioning, (ad nauseum), Afshar as a "fraud". There is absolutely no evidence for this whatsoever. Zilch. Indeed Afshar's experiment is consistent with a range of experiments by many people (including Einstein) that attempt to poke holes in quantum theory. That's a good thing. Not a bad thing. Carl.

Yes, good thing is to have discussion, and good thing is to reply to everyone who is interested in the topic. This is scientific behavior. But when somebody poses clear question, and you consciously avoid discussion this is a bad thing. Danko Georgiev MD 05:21, 3 March 2006 (UTC)

Prof. Afshar is under no obligation to discuss or defend his thesis to you or others. The scientific process works by you making your hypothesis and then supplying the evidence for the hypothesis. It is then up to the rest of the community to accept your hypothesis or not to accept it. This is an opt-in process. Nobody has to believe in the results. Nobody is under obligation to defend it or to reject it, not even Prof. Afshar. That is a very religious point of view to demand him to face up to an inquisition. Danko - if you do not like the results of the Afshar experiment, then write up your hypothesis and the empirical evidence supporting it and submit it for publication. Put it up on a website. For example, what is your evidence that V = 1? Please stop the incessant whining and personal crusading. Thanks. Forkhume 08:08, 5 March 2006 (UTC)

Regarding my "metaphysical rambling". If you do not understand what I am talking about then "metaphysical rambling" is as good a description as any other. But calling it such won't help to understand it any better. Without an understanding of the "metaphysics" (philosophical framework) out of which quantum theory evolves, the math can't evolve.

In rationalist forensic models "reality" is some hidden world exposed by clues within otherwise emperical data. Thus something like the wave function would be a "reality", exposed by clues such as only a 9% drop in the net intensity, of the detector data.

But in the spirit of the philosophical framework in which quantum theory emerges, one should treat the detector data as the reality under investigation, and the wave function as a way of describing that reality (but only while the data has yet to take place). Once the data takes place the wave function can be replaced by the data itself. The data represents itself better than the wave function. That doesn't mean the wave function should be thrown away.

But note how this is the complete inverse of the rationalist forensic model. The detector data does not describe the wave function. It is the wave function that describes (or predicts) the detector data.

The problem for neo-classical forensic rationalists is that they are philosophically forced to imagine the wave function as some independant reality that somehow "collapses" to produce the clues we otherwise call emperical data.

But the term "collapse", and indeed the entire mathematical framework of quantum theory, is a *concession* to classical rationalism, ie. if we are forced to speak in the language of classical rationality then the only way of describing the wave function, at the moment a particle is detected, is in terms of the wave function "collapsing".

But it is we who decide when the wave function collapses. If we want to be more specific about where a particle is to be detected, we don't even need any wave function - we can just wait for a particle detection to occur.

Carl

Dear Carl, very briefly, the photons happen to have linear momentum. Upon detection at the image plane the conservation laws demand that they must have originated from he corresponding pinhole. I did not make up this law, it simply is Nature in action! This reasoning was used both by Bohr and Einstein to establish which-way information. Also, I invite you to continue your discusion in my weblog (as you have) and not here. I will shortly reply to your comments in my weblog. Please heed the statement at the top of this page. Regards. Prof. Afshar 22:31, 25 January 2006 (UTC)

Dear Afshar, POSSIBLY YOU HAVE NEVER HEARD OF SUPERPOSITION OF QUBIT MOMENTA? If so, it is very bad for you. This elementary error is result of classical thinking, and IF you ask me, I can send you some papers published in Physical Reviews explaining how the idea of momentum in quantum mechanics should be correctly understood. You may have superposition of momenta, and interference of momenta, and for 18 years of studying physics you SHOULD know that simple fact. Danko Georgiev MD 07:37, 26 January 2006 (UTC)