Talk:Afshar experiment/Archive 15

Critiques are NOT original research!
Contrary to what Afshar says, critiques are NOT original research. Original research is Afshar's experiment, and every response to his work is NOT original research by definition. Nevertheless this does not imply that all critiques are correct, some [indeed all!] are wrong, as well as the Afshar's interpretation is wrong. I kept my promise to publish my thesis in strict mathematical language and one can download the full paper at PhilSci, ID3048. Georgiev, Danko (2006) Correct exposition of complementarity in Unruh's and Afshar's experiments. Indeed I hope all mathematicians like Lllinas, Looper, etc., recognize a strict mathematical argument written in extremely precise fashion, and try to find an error if they can. If they cannot find a flaw in my exposition, then I would like to request them not to vandalize my edits in the main text of articles in future! Regards, Danko Georgiev MD 01:14, 20 November 2006 (UTC)


 * I agree. Of course critiques are not necessarily original research; that depends on how well they are sourced etc.  --Michael C. Price talk 01:34, 20 November 2006 (UTC)


 * There is an "r" missing from the word "mirrors" on page three, first paragraph. :) --Carl A Looper 04:38, 20 November 2006 (UTC)


 * Regarding critiques. Effective critiques necessarily require effort on behalf of their authors, irregardless of whether their argument is otherwise "unoriginal" or regurgitations of accepted meanings. It is the effort (if nothing else) which makes them original.


 * The word "original" has at least two meanings.
 * "This was not the original idea".
 * "That's an original idea."
 * In relation to "original research" I'm assuming we mean "new" or "novel" research. Afshar's experiment can be considered original in this sense. The experiment introduces a new idea. In Danko's recent paper there are various new ideas. It is original research. --Carl A Looper 05:08, 20 November 2006 (UTC)


 * Whether a critique is "effective" has nothing to do with whether is it is "original" or on the "effort" put in by the writer. For example in the perpetual motion device example I used earlier it takes no effort to provide an unoriginal and effective critique by just mentioning the 1st law of thermodynamics.  One of the accusations against my critiques here was that they were "lazy" because I had expended no effort in their composition; perhaps so but irrelevant.  --Michael C. Price talk 09:51, 20 November 2006 (UTC)


 * Effective critiques necessarily require effort on behalf of their authors, irregardless of whether their argument is otherwise "unoriginal" (or original for matter). It is the effort (if nothing else) which makes them original (but not necessarily effective).


 * The perpetual motion machine argument was neither original nor effective. --Carl A Looper 11:07, 20 November 2006 (UTC)
 * So are saying that a perpetual motion machine is compatible with the laws of thermodynamics? --Michael C. Price talk 11:16, 20 November 2006 (UTC)
 * No, that is something you have imagined all by yourself. --Carl A Looper 12:27, 20 November 2006 (UTC)
 * I'm sorry to see you slipping back into your evasive ways, I was expecting more from you now. If a perpetual motion machine is incompatible with the laws of thermodynamics then it follows that any claim to possess one is effectively critiqued by referencing thermodynamics.  It seems that arguing by analogy or appeals to abstract reason are getting us nowehere.  From now on I will only address specific critiques of the critique text in the article.--Michael C. Price talk 13:33, 20 November 2006 (UTC)
 * I'm not evading anything Michael. It is just that I have no interest in perpetual motion machines or your analogy. If you are interested in such devices then by all means see where that goes. And if your reasoning leads you to conclude I am advocating perpetual motion machines then that is a problem with your reasoning - not mine. --Carl A Looper 22:13, 20 November 2006 (UTC)
 * You continue to be evasive. None of the latest points you make are relevant.  Analogies can be useful, as you well know, irrespective of any intrinsic interest or belief in the topic.  Deflecting the conversation like this is just a pathetic debating tactic.  --Michael C. Price talk 14:54, 21 November 2006 (UTC)


 * Well done Danko, I applaud your determination and hard work! I'm glad you did your homework and wrote a paper regarding your criticism of my interpretation. I will carefully read it and respond when I get the time. I suggest that all others interested in the topic do the same as Danko. FYI my paper has been accepted for publication in a refereed journal and will be published soon. Carl, Original Research in Wikipedia sense of the phrase is an attempt to publish one's ideas on Wikipedia without having it appear elsewhere (preferably a peer-reviewed journal.) Let the debates continue in earnest! --Prof. Afshar 05:36, 20 November 2006 (UTC)
 * Dear prof. Afshar, I hope after my complete exposition of mathematics you will agree that my contribution in the field is quite important. And as you may see from the paper Unruh's reasoning about his own experiment is inconsistent. One cannot claim "which way" as Unruh did, and claim pure state density matrix. The mathematics is clear as a crystal - in case of Unruh's setup there are no Fourier transforms, Airy discs, etc. However I am afraid his setup is equivalent to Afshar's setup, so my results apply to Afshar's experiment as well. Regards, Danko Georgiev MD 08:04, 20 November 2006 (UTC)


 * OR (Original research) in the context of wikipedia has a very clear meaning.  See No original research. Dndn1011 08:35, 20 November 2006 (UTC)
 * Dear Dndn1011, well but in Wikipedia is said that OR is some information that is not published! However this doesnot say not published "in peer-reviewed journal", so all published pre-prints are NOT counted as original research. See the Perelman's recent amazing contributions in topology, that have never been published in journal, but only available as preprint. Basicly, Wikipedia requires reliable source of the statements!!! If so, Afshar, me, Drezet, certainly do not represent OR since our theses are backed up with reliable sources, uploaded preprints at ArXiv, PhilSci, etc. Danko Georgiev MD 08:43, 20 November 2006 (UTC)
 * I agree. My point about the Cirtiques in the article some revisions ago was that it had the appearance of a personal collection of researched critiques that appeared to present itself as original research because it was put together by a contributor with the specific purpose of criticising Afhsar's experiement.  In other words it went too far.  In fact as the article stands now it is a lot better, but there as much that is quoted appears to have unknown ultimate validity, it still creates the impression of original research within the article itself.  Thinking about it, the critiques section should probably be renamed to "ongoing debate", this would help because the article would appear more neutral.  In any case it is a grey area.  Finally it is not necessary to have anything published in a peer viewed journal.  Published can mean having it simply appear on your website.    Although this seems counter intuitive and maybe even dangerous, there is no problem in reality because the definitions of valid references, original research and notability are decided by concensus in each case.  After all if Pythagoras put his (hitherto unknown) theorem on a web page and refered to this in his own article, after much debate and complaints of OR, notability and creating the article himself, it would probably be accepted because it is notable, was researched prior to the wiki article, has a neutral point of view and of course is proven to be correct. Dndn1011 09:41, 20 November 2006 (UTC)
 * Bad example with Pythagoras; this example is specifically dealt with by the guidelines and they say his theorem would not have been acceptable,prior to "publication" in the ancient world. --Michael C. Price talk 09:58, 20 November 2006 (UTC)
 * I was of course using Pythagoras as a hypthetical example where he was with us now and had just come up with the theory. Note that I said "Pythagoras put his (hitherto unknown) theorem on a web page and refered to this in his own article"... the point being that this can be an acceptable form of publication for the purposes of wikipedia.  Nothing prohibits refrences to original research even if this original research is not refereed.  If that were a requirement then it would not be possible to reference biographical information provided only on web sites.  As I have already said, providing a contribution is notable, verifiable and unbiased, it is not breaking wikipedia policy.  There are plenty of guidelines, but that is not the same as policy.  There is no policy that says "An article representing scientific theory is only notable if published in a refereed journal".  This would be a ridiculous policy because it would bias wikipedia towards a certain view, in this case the mainstream scientific view. Dndn1011 11:16, 20 November 2006 (UTC)


 * Some of the points you make are correct, but your conclusion is flawed: Wikipedia is intended to be biased towards the mainstream scientific view. And correctly so IMO.  --Michael C. Price talk 11:25, 20 November 2006 (UTC)
 * Then we might as well ask them to throw out everything that is not mainstream science, including any alternative belief systems. There is also the terrible danger in any case of new insights being excluded purely on the basis that they are not compatible with the mainstream. Further there is no indication that Wikipedia is intended to be biased towards the mainstream view.  It is indeed supposed to be unbiased.  That is of course the whole point of NPOV.  The easiest resolution of this is of course to simply have it tagged as a theory that has not been accepted by the scientific mainstream yet, which is currently the case with this experiment and Ashfar's conclusions.  This of course could change. Dndn1011 14:17, 20 November 2006 (UTC)
 * No, not throw out all non-mainstream views, but report on them and include sourced critiques for NPOV. --Michael C. Price talk 14:20, 20 November 2006 (UTC)


 * Yes, I agree with you there. But not with the statement "Wikipedia is intended to be biased towards the mainstream scientific view" which is in complete conflict with your last statement.  As someone who acuses others of blundering, you appear to be a bit of an expert yourself.  Perhaps if you tried to understand and reason with the point of view of others a little more before blundering in we might get done here a lot faster. Dndn1011 14:43, 20 November 2006 (UTC)
 * Depends on how you interpret "biased". Since Wikipedia lends extra weight to sources that are published in mainstream peer-review journals I think that can reasonably be interpreted as a bias.  Whether a bias is good or bad is another issue (IMO "good", as I previously indicated).  --Michael C. Price talk 14:51, 20 November 2006 (UTC)

Theory section is parody!
I hope someone will insert again the correct formulas for D and V. The theory section as is now is parody. V and D are not even defined mathematically. If they are defined mathematically as they should, it will be apparent that mathematical theorem cannot be violated by any experiment. I hope Drezet can insert again the relevant information. Danko Georgiev MD 10:47, 20 November 2006 (UTC)


 * I agree that the theory section is a shambles. I've got some background articles (including one of the so-called sources) I intend to read in detail soon, but my strong suspicion is the the equations are baloney.  Englert insists that what is called "distinguishability D" here is usually referred to as "predictability P", for example.  See ref 4 at Englert-Greenberger duality relation --Michael C. Price talk 10:58, 20 November 2006 (UTC)


 * There is an entire wikipedia article on the subject of that equation (Englert-Greenberger duality relation). I read it and in summary it seems to suggest  that D represents how like a particle the photon is measrued to be, and V represents how like a wave, each on a scale of 0-1.  Knowing which slit the photon goes through means D=1 and in this case there are no fringes observed thus V=0.  If on the other hand you can tell which way the photon went and also see fringes, then this would be V=1 and D=1 breaking the relation.  It seems pretty trivial to me, although it is not clear that it really adds anything to the article, as this is already stated previously without the need for a mathematical formula.  Dndn1011 11:40, 20 November 2006 (UTC)
 * But you can not see which way the photon went and see fringes. The fringes are a statistical property of many photons.  No photon that contributes to the build up of the fringes yields which-way information; no photon that yields which-way information contributes to the build up of fringes.  Each photon is either (1) absorbed by the wires (and can be henceforth ignored) or (2) focussed by the lens to yield which-way info BUT NOT BOTH.  If you insert a screen to see the fringes the photons that contribute to the fringe image do not get focussed by the lens to yield which-way information.  You might as well argue that the photons that pass through a conventional double slit apparatus violate complementarity since they behave like particle at the slits (D=1) and build up fringes on the screen (V=1).  Such an argument would be laughed out of court by any physics tutor at any institute.  This is why Drezet concludes:


 * To conclude, in spite of Afshart's claim we still need two experiments in order to exploit the totality of the phenomenon. As pointed out originally by Bohr, we can not use information associated with a same photon event to rebuild in a statistical way (i.e. by an accumulation of such events) the two complementary distributions of photons in the image plane and in the interference plane.  The hypothesis of Afshar that we only need some partial information concerning the interference pattern in order to reconstruct the complete interference is only based on the idea that the fringes already exist.  The whole reasoning is circular and for this reason misleading.


 * --Michael C. Price talk 13:56, 20 November 2006 (UTC)

Dear Mike, the whole idea that the image plane contains "which way" information in a pure state setup is mathematically inconsistent! If Bohr has said that the image plane contains "which way" information, Bohr is inconsistent too [I have never read Bohr]. But modern mathematical definition of complementarity is consistent! This is what I prove in my paper. If photons are nonpolarized they don't have "which way" information neither at the Fourier plane, nor at the image plane. If photons are polarized at the slits they will carry "which way" information both at the Fourier plane, and at the image plane. What decides the "which way" or not, is the density matrix of the photon, and this is what Afshar, Drezet, and others fail to see. Danko Georgiev MD 08:43, 22 November 2006 (UTC)

OK, I got the whole point. Yes, the link to Englert-Greenberger duality relation is enough, and then the whole "theory" section should be deleted. One should state at the very beggining of the Afshar article, that Afshar claims to have disproved [1] "Bohr's complementarity principle" and [2] the Englert-Greenberger duality relation. Note that these are not necessarily two identical things. While "Bohr's view of complementarity" might be wrong (indeed I little care what Bohr have said or not, the mathematical formulation of complementarity is clear and consistent), the duality relation is just a mathematical theorem, and one is NOT expected to interprete it in any way, but look at it just as a trivially true math expression. Please remove the theory section, which is like an "ugly patch" on the whole article. Danko Georgiev MD 12:21, 20 November 2006 (UTC)


 * Pending deletion or full revision I have tagged the theory section as disputed OR. --Michael C. Price talk 14:01, 20 November 2006 (UTC)


 * I had been going to suggest its removal, but I wanted to see what others said. OK It's gone. Dndn1011 14:20, 20 November 2006 (UTC)

Aha!
OK it really is worth looking at Afshar's QA stuff. There I reached an understanding of the experiment that I would not have gained from the article alone. This shows a difficiency in the latter. Here it is in layman's terms suitable for someone like me, perhaps: Accepted thinking is that if a photon passes through both holes then there can be no way to determine which hole it went through. Clearly this should be obvious. If a photon passes through both holes then it will not have passed through only one hole. The problem is that anything that detects a photon passing through a hole will in effect close the hole and so now it will be known which hole photons pass through, as they may only pass through the open hole.

Interference effects requires that the photon pass through both holes. Up until now a way to detect the path of the photons without destroying the possibility of the photons passing through both holes had not been devised. In Afshar's experiment, detection of which way the photon went is determined after it has had the opportunity to pass through both holes. As such it offers an opportunity to allow wave like behavior to take place, but also for a determination to be made of which hole each photon passed through at the same time.

If the experiement is performed with both holes open and no obstructions placed between the holes and the lens, the experiment will show which hole each photon went through, this being determined by which of the two detectors the photon hits. This is just as would be expected: being able to determine which way the photons went removes the possibility of interference which requires the photon passing through both holes.

However if a grid of wires is placed between the holes and the lens such that they align with the dark fringes of the interference pattern, an interesting effect is observed. With both holes open, virtually all photons are detected by either detector inspite of these wires being in the way. This is interesting because some photons should collide with the wires and significantly reduce the total numbers of photons detected, unless the photons pass through both holes in which case the wire would have minimal impact on the passage of the photons through the experiement, being aligned with the dark fringes of the interferences pattern.

From this it is concluded that after the photons pass through both holes in order to create an interference effect to 'avoid' the wires, they are detected as having passed through one or other of the two holes. This may be a violation of Niels Bohr's principle of complementarity, although the actual interpretation of this result is highly controversial at the present time.

Marginalia Warning: This is OR brainstorming from an armchair physicist: What I find facsinating about this is not the question of complementarity, but this: After the photons have exhbited wave like behavior necessary for 'avoidance' of the wires, they appear to have 'remembered' which hole they went through. Or which hole they went through is not decided until the moment of detection. I favor the latter. Basically, the photons do not exist until they are detected. It is impossible to know the path of a photon after all. We only infer it after it is detected. The photon does not travel in the sense we like to think. It just appears according to a set of rules. The 'choice' is not determined until detection occurs. Which leads on to another interesting thing... what happens if the two targets are at different distances, thus meaning a difference in time between detection depending on which target is to be hit? This might suggest that the 'decision' occurs not simply in space, but also in time. Of course because of the limit to the speed of light we would never in practice be able to make use of the delay to, for example, forwarn a more distant observer of the approach of a photon after seeing that it failed to hit our nearer target. This has started me thinking about relativity for some reason.... Dndn1011 19:56, 20 November 2006 (UTC)

All the above is completely wrong! If you already know the photon has passed through both pinholes to avoid the wires, then it is non-sense to say that the photon has passed through one whole only [inconsistency]. This last claim is taken without any proof, and indeed if you read the exact mathematical derivation as done in you will see the deep roots of arising the "mixing between channels" where the zero at the oposite hole is not "zero" but destructive interference of positive and negative quantum amplitudes. The fact that the photons has passed through both pinholes invalidates the classical "zeroing" as advocated by many. Everything else is pseudo-science. Danko Georgiev MD 06:19, 21 November 2006 (UTC)


 * All of the above in the first paragraph cannot be wrong, it is a description of the experiment. The inconcistency you describe is the whole point.  You appear to be denying the evidence because it is in conflict.  Yet the experiment appears to work as described above (unless I got some part wrong, do correct me there if I have). Welcome to Quantum Mechanics.  Nothing about the original double slit experiment makes sense.  This is why, it seems to me, complementarity was created.  It is a hack to avoid having to address inconsistency.  As a hack it worked because of the philosophical view that "There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature." (Bohr) In other words if we cannot demonstrate that photons must have passed through both holes and only one hole, then there is nothing to explain; there is no inconsistency because that inconsistency can not be shown.  And yet in this experiment too many photons are accounted to have gone through only one hole instead of both holes, compared to what we would expect if they had really done so, because of scattering off the wires.  The only way to avoid hitting the wires is for interference which requires the photon to have passed through both holes.  It seems watertight to me.  The hack now appears invalid, and now the question of wave particle duality seems to be beckoning for a real answer.  If this is accepted then the only way I can see of solving the problem is to note that an inconsistency is usually due to a false assumption.  Since we cannot measure the path of an individual photon, but merely infer it, I argue that we have to start thinking about photons in a different way (and maybe electrons too... who's going to do that exepriement then?).  I would say that this apparent inconsistency means the assumption that photons pass through anything is wrong, and that photons do not actually travel at all.  In fact they probably do not exist before they are detected.  This solves the conflict, but of course it also creates many more questions.  But hey that's good.  Perhaps QM has been barking up the wrong tree.  This does happen from time to time in science, as I understand it.Dndn1011 09:24, 21 November 2006 (UTC)
 * Regarding the issue of inconsistency. The formalism (maths) of QM is not inconsistent; it has been verified again and again.  Bohr's quote in the critique section indicates that complementary is just our way of describing the precise maths.  If someone arrives at an incorrect description of a consistent set of maths it is because their description is flawed, not the because the underlying theory of quantum mechanics is flawed.  This relates to the whole debate about the interpretation of quantum mechanics. --Michael C. Price talk 15:02, 21 November 2006 (UTC)
 * A proven mathematical theorem is proven forever (unless there has been a mistake). This does not mean however that the theorem represents reality.  Such it was with Newtonian mechanics.  All the math worked, and it seemed to match reality and still is extremely useful.  However it fell short of reality.  Here we potentially see an inconsistency that will not change the theories thus devised and their proofs which are great as far as they go.  All the expriment might show is that these theories do not go far enough.  Certainly I find it a bit of a cheat to explain the double slit experiement away by saying "We do not need to understand why it works like it does, we just accept that it does".  Who knows when we actually develop a thoery that explains it properly a whole load of other things might fall into place. Dndn1011 16:05, 21 November 2006 (UTC)
 * The empirical basis of the formalism is not at issue, merely the interpretation of the formalism. For this see interpretation of quantum mechanics, to see how people try to understand the double slit experiment or Wheeler's delayed choice experiment (which is very similair to Afshar's).
 * Actually Wheeler's delayed choice experiment is a thought experiment and could not work because of the problem of the speed of light. There is no way of being able to choose the right moment, unless you can create a device that fires a single photon at a predictable moment in time given some kind of signal and synchronise the change over with that by infering where the photon would be.  However this does raise other interesting points, like what happens when various bits of the apparatus are in motion instead of stationary?  And what happens if a half silvered mirror is placed just after the holes?  What fun.  And how does a half silvered mirror work anyway with single photons?  Dndn1011 17:29, 21 November 2006 (UTC)
 * Being a thought experiment does not lessen its utility; thought experiments (like analogies!) are useful tools for checking the internal consistency of both the formalism and any interpretation of the formalism. I don't understand your point about the speed of light, unless you mean it could not work in practice because of it huge size -- but it's a thought experiment, so who cares?  As for the question of what the half-slivered mirror does, we can only give a precise answer in terms of wavefunctions (which you may not find satisfactory).  Assuming an equal probability of transmission vs reflection then the incoming photon's wavepacket is split by the mirror into two: the probability amplitude of the half that is transmitted is multiplied by a factor of $$\frac{1}{\sqrt{2}}$$ but is otherwise unaltered.  The reflected half has its direction of travel altered (obviously) but its probability amplitude is multiplied by $$-\frac{1}{\sqrt{2}}$$ (note change of sign).  --Michael C. Price talk 22:22, 21 November 2006 (UTC)
 * It is as I suspected that in fact a half silvered mirror is only explained in terms of wave functions and so does demonstrate the same kind of paradox as the double slit experiement, although if we hold to Bohr's philosophy there is no need to explain the effect, it just is that way. You are right that I don't find this satisfactory.  As for Wheeler's delayed choice experiment, I am reasoning that the thought experiment does not take into account that in reality limitations of the speed at which information can be moved around menas that there would be no way of observing this experiement in action.  It is never-the-less interesting.  In a variation on it take a half slivered mirror and a beam of photons.  Place one detector a few inches away, and the other a light minute away.  There is a 50-50 chance of going to either detector, but one detector will take a minute to pick up the photon, while the other detects it almost immediately.  If we can fire a single photon and know it was fired (I have no idea if that is technically possible) we can know that the photon will impact the more distant target if it has not been detected on the nearer target.  However there is nothing we could do to intentionally change the course of this photon after we realise that the photon is heading to the more distance target because any information about the photon can not travel faster than the photon itself.  Once the photon is actually detected we can theoretically trace the enitre life of the photon, and even the time it impacted the mirror.  But something tells me that such a theoretical calculation would have no basis in reality.  We assume that the photon hit the mirror 1 minute before it was detected at the more distant target, but we have no way of verifying this.  Again it is just a natural assumption and it could be wrong.  Actually this gives me an idea.  The photon emitter might simply create some kind of probability function that takes into acount all possible paths a photon could take with the associated probabilities, the universe rolls some kind of cosmic random number generator and selects one result.  And yet it does not end there does it?  The result is measured, but what does measurement actually mean?  The photon hits the target and lights a lamp which emits photons that hit your retina... and the wave function collapses only then?.  If there is anyone to observe the result of the collapse of a wave function, does it ever collapse?  We could ask Schrödinger's Cat about that.  If you record the detection on film, and someone else looks at it, has the wave function callapased for them only?  Is it still uncollapsed in your frame of reference?  Does it collapse for you when they tell you?  This is heading for the wierd idea of observer created reality.  If the tree falls in a forest and there is no-one to hear, perhaps it does indeed make no sound.  I know that is pseudo-science, don't bother telling me heh... Dndn1011 00:09, 22 November 2006 (UTC)
 * It is not pseduo-science; these issues are taken seriously, which is why the whole topic of interpretations of quantum mechanics is so huge. Again I must recommend that you read up on the subject: start from interpretation of quantum mechanics or some related topic and work outwards -- that's what Wikipedia's here for.  --Michael C. Price talk 07:53, 23 November 2006 (UTC)
 * Thank you, yes I am investigating and reading up more in an effort to understand better. It is only because of wikipedia that I started to get interested in this again.  But the double slit experiement has been bugging me ever since I found out about it at school over twenty years ago.  Over this time I have evolved in my mind various strands that I'd like to pull together someday.  It is of course my limited training in mathematics what holds me back more than anything.  But sometimes to learn to swim there is nothing better than throwing yourself in the pool. Dndn1011 09:12, 23 November 2006 (UTC)


 * Danko, I did read your paper, and sadly I have to report that you have made the same trivial errors previously pointed out to you by me, Unruh, Drezet, and other expert physicists. The validity of which-way information is ensured by the conservation laws implicit in the Hamiltonian of the unitary time evolution of the wavefunction. You further say that "the zero at the oposite hole is not "zero" but destructive interference of positive and negative quantum amplitudes." No, it's not! The reason we see only one of the detectors click, is because there is only a single photon present in the total wavefunction at any moment, and as soon as it is detected (destroyed) at one of the detectors, the entire wavefunction collapses (nonlocally disappears), and no longer has any physical manifestations whatsoever. Any other explanation of the situation is pseudo-science. Regards.--Prof. Afshar 06:34, 21 November 2006 (UTC)

Dear Afshar, please don't use bold style. Considering your post, I don't see any mathematical claim there, you speak complete non-sense. "Which way" information is defined as existent "one-to-one correspondence" and as you see in the building block of Unruh's setup, whether there is one-to-one correspondence between entry points and exit gates, has nothing to do with the linearity of the Schroedinger equation. In all cases the evolution is described by the linear Schroedinger equation, but NOT in all cases there is one-to-one correspondence. Please show some competence whatsoever on the topic, and don't post spam on Wikipedia! Danko Georgiev MD 09:02, 21 November 2006 (UTC)


 * Although I agree that the use of bold is bad form, I see no spam going on here. Afshar is quite within his rights to answer points you raise here.  Do you define spam as anything you disagree with?  Incidentally you may wish to review the rest of this long debate, where Afhsar has mentioned that a paper will appear in a refereed journal soon and that he has support of respected physicists.  Although this in itself is not proof of anything, it might be wise to tread carefully before throwing accusations of incompetance around.  I of course do not need to tread carefully because I have nothing to loose other than dignity, and I have lost that so many times it does not hurt any more.  Curiously though even I for the most part refrain from direct insult. Dndn1011 09:46, 21 November 2006 (UTC)


 * Danko's argument is extremely interesting. The axiomatic definition of V is no longer the same thing as an emperical definition of 'V' as might have otherwise been assumed. One can not math consistently say A and B. One must say A or B. And the argument for math consistency is an extremely powerful one. The prinicple requires (correction: it imposes) a limit on the inferential meaning of the "which way" observable, ie. in spite of the observable, not because of it. While the observables originally "forced" the principle into play it is now the principle which "forces" the observables into question (correction: into play). Which is almost a relief. Bohr's interpretational crutch, "there is no quantum world" is possibly incorrect. There is a lot more to be explored in relation to this question. --Carl A Looper 20:24, 21 November 2006 (UTC)
 * Dear Carl, I would like to THANK not for the agreement, or disagreement with what I say. I want to THANK for the fact that you (maybe) "have seen/understood" my mathematical argument. In a crystally clear way, I show that complementarity is a deep mathematical formulation of QM, and has nothing to do with interpretational aspects. But ... unless one gets the deep mathematical idea of complementarity, one will stay on the surface and will be easily lead into delusion! The example with Afshar is obvious - he takes "which way" because "others say so", and claims K = 1 [distinguishability, "which way"]. Yet, once assuming that the quantum interference is "there" [not necessarily detected, just mathematically postulating it is enough!] you will calculate K = 0, because the amplitudes at both pinhole images are $$|\psi_{1}|=|\psi_{2}|=\frac{1}{\sqrt{8}}$$. Unless one shows mathematical error in my thesis, it will be the only true interpretation of the whole setup. Danko Georgiev MD 02:12, 22 November 2006 (UTC)


 * On the lighter side. What this means is that since the principle of complementarity makes the "which way" observable inferentially unstable then if you were to connect a 'brain' to the detector you should not program it to conclude there is an associated pinhole. Your brain will need to grow arms and legs and walk over to the pinhole to confirm it's existence. Before jumping to any conclusions keep in mind that the pinhole could be hologram. So adding arms and legs is not a bad idea. However, it is not mathematically inconsistent to program your brain to just think a pinhole is there. More often than not it will be. --Carl A Looper 01:57, 22 November 2006 (UTC)


 * Dear Carl, your last add is deviation from the topic and has nothing to do with Afshar's setup. I also have clearly stated this in my paper, one can interprete any way he likes the setup, but this will be inconsistent with the current mathematics of QM. So, you can define that $$V^2 + K^2 = 2$$, $$V^2 + K^2 = 17$$ ... but this will be need revision of the fundaments of QM. Whether you can program the brain to believe in "wrong thesis" or not, is not relevant to the discussion. Noone argues that there are no people that insist on wrong ideas. Afshar and others are example that such people do exist. Danko Georgiev MD 02:12, 22 November 2006 (UTC)


 * My apologys Danko. The add was a deviation from the issue at hand and I welcome your reprimand with respect.


 * Considering the interpretation of the whole setup, I am closer to "shut-up-and-calculate" interpretation of QM, than any other interpretation. Yet, I am realist, so for me the quantum amplitudes [state vectors] are realities out there. Thus superpositions are "real" and the photon can take one path or both at the same time [similar to MWI, Penrose's OR, Cramer's TI], yet unless the MWI, I do think that everything happens in one single Universe. Whether you will call the "Multiverse" with the name single "Universe" is a matter of definition. So all the peculiarities of the quantum mathematics are instantiated by the "Universe", and each quantum phenomenon has underlying strict mathematical definition. To interprete like Afshar, without understanding the underlying mathematics of your own work is equal to "suicide". Afshar still has not written a single formula in his post to critiques. He only "does philosophism", not science Danko Georgiev MD 02:28, 22 November 2006 (UTC)


 * But let us stick to the issue at hand and refrain from inferring more than we should. And by that I mean deviations into theorys about Afshar. On this issue you will not find any support from me. What is of crucial importance is your paper and I don't know if you realise that yet. --Carl A Looper 03:08, 22 November 2006 (UTC)


 * Dear Carl, I also don't like to beat about the bush discussing irrelevant topics. If you stick to the topic, and ask concrete questions on my paper, I will be able to answer concretely also. I am glad, that someone [you] has seriously decided to check/verify all details of my paper. Danko Georgiev MD 03:49, 22 November 2006 (UTC)


 * I'll send you the computer simulation when it's done. I'm writing it up in C++. But I'll be appling it to the Afshar experiment instead of Unrah's (for something to do).--Carl A Looper 05:11, 23 November 2006 (UTC)


 * A quick question: does not Danko's paper still make the assumption that there are paths? As we have no way of verifying that photons take paths rather than just appear when detected, this is an assumption.  Secondly, there is the question of how the exit direction depends on the entry direction in Unruh's examples.  This implies some kind of state information that is retained while the photon 'travels' through the experiment.  This would seem to be the most interesting aspect of such examples, leaving asside the question of complementarity for a moment.  Surely a mathematical representation of the output versus input 'states' is impossible because the two paths are mathematically equivalent.  Unless I am missing something.  If I am I would be grateful if you could poitn me in the right direction. Dndn1011 09:53, 22 November 2006 (UTC)
 * Dear Dndn1011, if you read carefully the introduction of all concepts step-by-step, as done in my paper, you will see that "the path" assumption is not classical idea at all, but we speak of two different types of probability distributions [mixed type vs. pure type], what really matters is that "which way" has meaning only as one-to-one correspondence. In the simple interferometer with 2 half-silvered mirrors and 2 full silvered mirrors, you have "pure state" distribution [superposed paths 1 & 2] and have one-to-one correspondence between entry gate and exit gate. However, in Unruh's interferometer the conclusions are exactly the opposite: you have one-to-one correspondence between path 1 and 2, with the exit gates, only if you postulate "mixed state" distribution and so non-superposed paths 1 & 2. You better read my paper for further details. Danko Georgiev MD 11:00, 22 November 2006 (UTC)


 * I would appreciate if you continue discussing Danko's "paper" on his user page. Thank you.-- Prof. Afshar 05:16, 23 November 2006 (UTC)