User talk:Stigmatella aurantiaca

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You could've sent an e-mail[edit]

Re this (assuming it was you, and not someone pretending to be you).

Well, maybe you did. Haven't checked my inbox in a few days. Either way, I've got a little flair for the dramatic myself, so no hard feelings about the faux vandalism.

Anyways... I won't get into the intricacies of my various digital security measures, but suffice it to say that disclosing what I disclose does not make me significantly more vulnerable to theft. I appreciate your concern, though. Lost my glasses the other day while on vacation, and after looking everywhere we're pretty sure they were stolen, so it's always useful to be reminded that there are bad people out there. If someone does crack one of my accounts, feel free to say "I told you so," but, like I said, I'm fairly confident that that stuff is secure.

And happy New Year's to you too. Don't think I ever apologized for my naïveté lo those 13-going-on-14 months ago, so, sorry about that. Looking back in my contribs to figure out your riddle, I was mortified at how dumb I was back then. I'm sure I'll say the same thing about myself now in a year, but hey, guess that's better than the alternative. — PinkAmpers&(Je vous invite à me parler) 01:55, 1 January 2014 (UTC)

It was me, all right, just being in a playful mood. And yes, I could have used email. I don't have any concerns about revealing my email address to you, which is obviously derived from my name. I've read your position on anonymous usernames on Wikipedia, and to a certain extent I agree. Just wanted to say that I've watched you grow up and mature on Wikipedia, and I'm pretty impressed. Stigmatella aurantiaca (talk) 02:08, 1 January 2014 (UTC)

Duh... but hey...[edit]

Re the "good faith" part, see this. But hey... keep up the good work and happy 2014! :-) - DVdm (talk) 18:51, 3 January 2014 (UTC)

File:Solar storm 2003-10-26 (SOHO-EIT Ultraviolet 195 Å).png listed for deletion[edit]

A file that you uploaded or altered, File:Solar storm 2003-10-26 (SOHO-EIT Ultraviolet 195 Å).png, has been listed at Wikipedia:Files for deletion. Please see the discussion to see why it has been listed (you may have to search for the title of the image to find its entry). Feel free to add your opinion on the matter below the nomination. Thank you. Stefan2 (talk) 19:12, 12 January 2014 (UTC)

Please have a look[edit]

In the article on the Double-slit experiment, 2.3, a new editor to Wikipedia has made some changes that I do not comprehend. Communication with him is extremely difficult since English is not his native tongue, and possibly because of simple difficulties in formulating statements so that others can understand them. He wrote:

The classical explantion are the Fresnel and Arago laws, which state that orthogonal polarization does not interfere. The 45° polarisers force the two orthogonal polarizations to become parallel polarizations, which can interfere. A more complicated measurement uses two quarter wave plates at the slits, which transforms a linear to a rotating polarization.[38] However, when two oppositely rotating waves are added (at the detector), the rotation disappears. Also, according the paper, the "not interference" pattern is actually the sum of two interference patterns which are shifted 180° to each other.

To me, "orthoganal polarization does not interfere" is meaningless. I think he means that when there are two polarizations involved and they are set at 90° to each other, they will not interfere. That statement would fit in with the Scientific American quantum eraser experiment. Then, if he is still talking about the SciAm experiment, which uses ordinary sheet polarizers, the part about "45° polarizers" should refer to a single polarizer introduced somewhere midway between the double-slit diaphragm and the detection screen. So if that is what he means then the first part should be o.k.

The rest of it, however, puzzles me. He is evidently describing the Walborn et al. double-slit experiment Delayed_choice_quantum_eraser 1.4. It indeed uses two quarter wave plates at the slits, but they are rotated 90° to each other. So he should say that the apparatus "transforms wavefunctions from the left slit into one circular polarization (e.g., clockwise), and wavefunctions from the right slit into the other circular polarization (e.g., counter-clockwise).

The above reasoning would be consistent with what he says next, but I think he is dead wrong where he says that "when two oppositely rotating waves are added (at the detector), the rotation disappears." That isn't the way the experiment works at all. Two copies of the same wavefunction intersect the detection screen, they do not have a productive superposition, and one gets what would only make a contribution to a single-slit diffraction pattern from each of the slits. The experiment uses a third polarizer, inserted into the path of the entangled photon on the "upward" path to the top detector, to change the polarizations of the wavefunctions on the two paths coming through the double-slit diaphragm each into two sets of regular polarization coming from each slit, and the coincidence counter needs to be used to assure that one can sort out all of the photons with interfering wave functions that have the same polarization and phase. The part about the "not interference" pattern being the sum of two interference patterns that are shifted 180° to each other is not relevant to what happens when the two beams of circularly polarized photons are merged on the detection screen. Interference is impossible at that stage. It is, instead, something that he got by understanding that no interference pattern would be visible on the detection screen if both circular polarizations were changed into regular polarizations at the same time. That happens to be impossible because the third polarizer can only affect either the clockwise wavefunctions or the counterclockwise wavefunctions that went through the double-slit diaphragm.

I am running out of patience, so I would deeply appreciate another set of eyes on this article.

Thanks.P0M (talk) 21:49, 4 February 2014 (UTC)

A first glance leaves me just as puzzled as you. I haven't figured yet if he knows what he is talking about but language difficulties leave him unable to express his thoughts properly, or if he is clueless but language difficulties leave us unable to determine his ignorance. I'll let you know more of my conclusions later. Stigmatella aurantiaca (talk) 22:13, 4 February 2014 (UTC)
I just noticed the talk page discussions on this section. Stigmatella aurantiaca (talk) 22:29, 4 February 2014 (UTC)
The discussion on the Delayed_choice_quantum_eraser talk page is where I have tried to pin him down more. Unfortunately he never responds by accepting something I have argued for. If he notices at all he may change what he has written. But in the article he says that where the two circular polarizers are added to a regular double-slit experiment there is no interference. In the talk page for that article, he says that there is interference. In the Double-slit experiment page he says there is interference, and he really gets things mixed up. At least that is the way I see it. An individual whose work involves all this stuff has told him he is wrong/incomprehensible, but he pays it no mind. I don't want an edit war.
The Delayed_choice_quantum_eraser article was much better before he started in on it, but I have resisted reverting because of the edit war possibility. I've had a couple people point out details in the schematic diagrams I presented, indicating that several people with good physics knowledge went through the article and only found where I had swapped some polarities to be wrong.
Thanks for helping with this. I can call on one of my colleagues whose position in our physics department is to teach quantum mechanics, but I hate to bother him. P0M (talk) 22:42, 4 February 2014 (UTC)
I'm having trouble figuring this paragraph out:
"A more complicated measurement uses two quarter wave plates at the slits, which transforms linear to circular polarization.[38] However, when two oppositely rotating waves are added (at the detector), the rotation disappears. Also, according to Walborn, the "not interference" pattern is actually the sum of two interference patterns which are shifted 180° to each other."
I've read what you've written above, but I'm going to have to read the paper myself before tackling this paragraph. Could you go over what I've done so far? Thanks! Stigmatella aurantiaca (talk) 05:22, 5 February 2014 (UTC)
Everything looks fine with what you have done so far.
The reason you are having trouble with what is written above is that it is wrong. I will refrain from characterizing it further. Here is the deal:

Walborn EtAl QuantumEraser.svg

First look at what happens to the photon that is on the diagonally downward path, path s. (Take the polarizer out of the upper path, path p, until later.)
QWP1 and QWP2 are different. One produces clockwise polarization and the other produces counterclockwise polarization. When the two paths from the Double Slit apparatus merge at the detection screen they can't productively interact with each other any more than a left-threaded bolt can turn into a right-threaded nut. So Ds will see a couple of diffraction patterns just as it would see them individually if first slit A were blocked and then slit B were blocked. The whole point of doing it this way is so that this incompatibility can be "erased." The rotation doesn't "disappear" in any sense, at least not at this point. That is why the quoted passage is wrong.
To "erase" the which-path information the experimenters next introduce the polarizer into path p. Depending on which way POL1 is oriented, the interference pattern manifested on Ds will be one pattern or that pattern slightly displaced (fringe and antifringe).
Walborn's article has a summary by diagrams at the end. The short version is: Fig. 2: with QWP1 and QWP2 removed an interference pattern is observed at D2. Fig. 3 With QWP1 and QWP2 in place, interference has been destroyed. Fig 4: When POL1 has been added in the upper path, and POL1 set to θ interference is restored in the fringe pattern. Fig. 5: When POL1 is set to θ+π/2 interference is restored in the antifringe pattern.
I hope this helps. Right now the same editor has created contrary accounts across the 3 articles involved with double-slit experiments.P0M (talk) 06:44, 5 February 2014 (UTC)
Before I forget this stuff, I've just had another run-through of the article. I think I've reviewed this better now, and that the following is an accurate summary:

Quarter wave plates 1 and 2 are set at 45° and -45°. Because wavefunctions coming through each of the double slits has a circular polarization opposite to the other, the wavefunctions coming through the two slits cannot "line up" with each other. Therefore it is impossible that interference phenomena should be manifested at D[s].

Since wavefunctions emerging from slit a and slit b have orthogonal polarizations, there is no possibility of interference. We can recover interference by placing a polarizer in the path of beam p and orientating it at +45◦ to select |+ip or at -45◦ to select |−ip. The interference pattern is recovered through the coincidence detection of photons s and p. Notice that the fringes obtained in the two cases are out of phase. They are commonly called fringes and anti-fringes.

Let's say that blue-path wavefunctions are clockwise and red-path wavefunctions are counter-clockwise. When POL1 is activated half of the blue- path wavefunctions and their paired red-path wavefunctions are transformed into polarized states that can interfere. The other half will remain untransformed and so will not interfere. It is then necessary to use the coincidence counter to select only those photons at Ds that are match by photons at Dp. Doing so will reveal interference fringes. When POL1 is rotated to its second position, the alternate group of circularly polarized photons will be transformed into ordinary polarization, and a second interference pattern can be revealed by selecting those photons at Ds that are matched by photons at Dp.

I hope the above will be helpful.P0M (talk) 08:28, 5 February 2014 (UTC)

Thanks, you've made things very clear for me! I deleted the problematical paragraph, which involves discussion of a primary research source. Wikipedia policy discourages overuse of primary research sources, preferring use of reliable secondary and tertiary sources. Direct discussion of primary source material, placing it in proper context etc., necessarily involves some degree of (horrors!) WP:OR on the part of the editor. Detailed discussion of a primary source may be acceptable in a technical article such as Delayed choice quantum eraser, but is unacceptable in an article like Double-slit experiment, which should be accessible to secondary school and first-year college students. If DParlevliet tries to reintroduce the material into Double-slit experiment, I'll just delete it on that basis. I doubt that I'll have any problems with edit warring. I'll keep an eye on Delayed choice quantum eraser, Wheeler's delayed choice experiment, Quantum eraser experiment and will try to help. Stigmatella aurantiaca (talk) 09:12, 5 February 2014 (UTC)
I've been stifling myself for some time now. Finally I got somewhere on Talk:Delayed_choice_quantum_eraser. (The contributor who uses an IP is somebody who actually works in the field, and he is getting more direct in his comments which were added just before mine but are lowest on the page.) It is clearer now that DParlevliet is all mixed up about the several different configurations of the experimental apparatus and about when, in the process of adding in polarizers of a couple of different types, you finally get a couple of interference patterns that can be pulled out with the help of the coincidence counter. He has to be forced to carry on a responsive conversation.
Thank you very much for your help with these articles. By the way, one of my main reasons for editing Wikipedia articles is that 60 years ago I was a high school student who rarely could find useful information about science topics, and some of the materials I came across were wrong or at least very misleading. What we are doing can help people in that situation who are located all over the world. P0M (talk) 13:41, 5 February 2014 (UTC)


129.217.159.124 articulated a concern that was niggling at the back of my mind without my really being aware why I was bothered. Although I substantially cleaned up the wording, the following still represents DParlevliet's thoughts:

"An alternative, classical explanation of the above observation follows from the Fresnel and Arago laws, which state that orthogonally polarized beams of light do not interfere. The 45° polarizer filters parallel components from the two orthogonally polarized beams of light, which can then interfere."

As 129.217.159.124 pointed out, this is all part of DParlevliet's "classical physics is enough to explain seemingly quantum experiments" agenda. What are your thoughts? Stigmatella aurantiaca (talk) 13:32, 5 February 2014 (UTC)

I see that we are communicating in real time. I agree with 129.217.159.124. Most of the time DParlevliet's mentions of classical physics do not improve things for the average well-informed reader. They just get in the way. I tried to explain to DParlevliet that quantum mechanics subsumes all valid parts of classical physics, but doing so had no effect. (129.217.159.124 is the one with lots of real-world experience with quantum optics.) It is confusing to readers to be told that something happens because of some principle with an unfamiliar name. The reader may think that it is important to understanding the experiment to become familiar with that principle. That would be a little like believing somebody needs to understand the principle of the internal combustion engine to understand why driving an automobile can be a dangerous enterprise.P0M (talk) 14:09, 5 February 2014 (UTC)
I was wavering between adding an explanation why the classical analogy doesn't universally hold versus just deleting the paragraph, and your comment pushed me into deciding to go the KISS route. Stigmatella aurantiaca (talk) 14:40, 5 February 2014 (UTC)
That's fine with me. P0M (talk) 16:08, 5 February 2014 (UTC)
I followed suite by deleting the comparable classical argument from Delayed_choice_quantum_eraser. I can't quite believe how disrespectful he is of the intellectual accomplishments of four university professors and all the other physicists who have not challenged their research. Now, if things settle down a bit, I will try to fix his English for the parts of his work that remain.P0M (talk) 16:34, 5 February 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I examined the version of Delayed choice quantum eraser from 1 Oct 2013 and agree that probably around 75% of the differences between that version and the present version were non-productive, and the diffs are pretty intertwined so that fixing them through plain editing won't be easy. Do we have a three-person consensus to revert to that version? I'm willing to be the person actually making the revert, thus being the scapegoat. Stigmatella aurantiaca (talk) 17:36, 5 February 2014 (UTC)

DP just reverted my deletion, so I guess we are in for some kind of an edit war. The IP contributor just swore off the whole thing, being entirely too frustrated with DP. I think his parting words were that it ought to be reverted. But there are only two of us now. Do we need a third? P0M (talk) 18:33, 5 February 2014 (UTC)
We have 129.217.159.124's statement on record, so the consensus still exists, no problem there. However, I won't be much good in helping you with subsequent edits to this article. I know enough to appreciate the issues and to contribute to physics articles at a college lower division level, but as Dr. McCoy might say, I'm a molecular biologist/senior software engineer, not a quantum mechanic. Face-smile.svg Stigmatella aurantiaca (talk) 18:49, 5 February 2014 (UTC)
I can always check with our quantum mechanics expert in the physics department. He doesn't like to edit, probably because of the things we've been encountering, but he will answer any questions that might come up. I asked the IP to give me any feedback needed on the earlier version. He entered into our conversation by sayuing that the article was o.k. until DP started to make changes. If I need to I'll have my local colleague go over it too. Besides, the articles that go beyond undergrad physics are the full-bore articles like Quantum mechanics, which seem to me to be too hard for anybody beyond people with physics backgrounds. The articles you and I are looking at should just be reporting on things like what people would see in the lab, not giving a full physicist-style mathematical model in all its details. P0M (talk) 18:59, 5 February 2014 (UTC)
P.S. My level is more Chekhovian even though my temperament is perhaps more spockish or puckish.P0M (talk) 19:05, 5 February 2014 (UTC)
I did the revert. Stigmatella aurantiaca (talk) 19:11, 5 February 2014 (UTC)
Thsnk you. P0M (talk) 19:31, 5 February 2014 (UTC)
It's been years since I've come even close to an edit war. DP has gone back to his version. How many time can I revert in a 24-hour period (or is it in a calendar day) before I get sanctioned/banned? Thanks.P0M (talk) 21:49, 5 February 2014 (UTC)
Three times in 24 hours. At this moment, I've used two reverts, DP one. Keep close count. Stigmatella aurantiaca (talk) 23:42, 5 February 2014 (UTC)
Not just global reverts, but reverts of individual disputed sections count. Be careful. Stigmatella aurantiaca (talk) 23:47, 5 February 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I've taken one very garbled passage and tried to straighten it out. It is up for discussion, and since DP is the one who made the original it would seem that he should be the first to correct any points at which I've missed his intended meaning. So far no response. P0M (talk) 23:09, 6 February 2014 (UTC)

With further research into diffs, etc., it seems clear that the basic form of the whole block of text was originated by someone who registered an identity with Wikipedia, made that edition, and then never made any other contributions. So it is not likely that he could be contacted. I see some benefit to the part we've already discussed, but the rest of it appears useless to me.P0M (talk) 12:17, 7 February 2014 (UTC)
I've had a bit of success deciphering the second paragraph. Hidden in that paragraph is an explanation why the two sets of interference fringes are complementary to each other. Assuming no losses due to absorption, conservation of energy requires that the reflected and transmitted beams from BSc add up to 100%, so the phase difference is 180 degrees. You're right, though. Most of it is useless. Stigmatella aurantiaca (talk) 12:37, 7 February 2014 (UTC)

Notice of Edit warring noticeboard discussion[edit]

Information icon Hello. This message is being sent to inform you that there is currently a discussion involving you at Wikipedia:Administrators' noticeboard/Edit warring regarding a possible violation of Wikipedia's policy on edit warring. Thank you. — Preceding unsigned comment added by DParlevliet (talkcontribs) 11:22, 6 February 2014 (UTC)

Any way forward?[edit]

I can see no hope of communicating with DP. He confuses a potential for interference with interference itself. He argues backwards. He would argue, it seems, that a ton of hamburger is the same thing as a steer. Each time since these discussions with him began he simply drops an argument that he is not winning and a while later the same unreasonable conclusion comes up again.

His basic mistake is to believe that a photon split in the double-slit diaphragm and processed with two quarter wave plates so that the two photon-splits have opposing circular polarization can superimpose with interference. He is almost correct, because all of the "information" continues to exist, but the "information" splits can't reach each other because of their opposite chirality.

His next mistake is to indicate that mathematically you can fix the chirality mismatch after light exits the two quarter wave plates, but he fails to see that this is a change done to the photon-splits without which they cannot interfere. He says, in effect, "Look! Interference was there all along." What he wants to do could be accomplished by using a half-wave plate on top of one of the two quarter-wave plate. That way there would be consistency between the chirality of the two sets of photon-splits. However, that is also what is accomplished by using the POL1 device in the signal wing of the experimental apparatus. The main difference is that the experimenetal design uses something that takes two steps to get at all of the photons, mainly because in that way the experimenters can engineer a way for re-polarization to occur at different distances in time from initial photon emission.

I can't get through to him, and except for Cthugha82 nobody has ever stepped in to say that my arguments are correct. I think that such reinforcement might be helpful. P0M (talk) 21:59, 8 February 2014 (UTC)

I'll join in after I've finished studying the paper. But I'm also studying Entity Frameworks and MVC 4 for a new project, and my vacation ends Feb 17, so I won't be able to participate heavily after a week. Stigmatella aurantiaca (talk) 08:26, 9 February 2014 (UTC)
Your recent summary is extremely helpful. DP repeated his twisted quotation to argue point 3, however. Unless everybody reinforces the judgment that he is not proving his point (and he accepts the judgment of a bunch of PHDs) he can make no progress.P0M (talk) 16:28, 9 February 2014 (UTC)

frustration -- do i need to learn Dutch?[edit]

As you may be able to tell, I am getting more and more tired of receiving either no response or a specious response from DP. I am trying to assume good will, and so far I have succeeded. However it seems to me that RockMagnetist was more right than I wanted him to be, and all we can do is to insist on solid research in peer-reviewed publications. For me, at least, anything else gets deleted. Are you familiar with an old book called Games People Play? Its central point is that sometimes the motivation for unproductive or disruptive behavior is other than it may seem to be on the surface. Whatever is going on, I have much more important things to do than to straighten out anybody's twisted skeins of reasoning.

Have I been spouting errant nonsense and everybody is too polite to call me on it? P0M (talk) 17:30, 10 February 2014 (UTC)

programming[edit]

As a teenager I read Alfred Bester's novels, and one of them had something in it about learning a foreign language by the use of a computer program that would measure and keep track of a student's progress. Moreover, it was all done with spoken Vulcan or whatever the target language was, and pictures. As a grad student coming back to the U.S. after 4 years in Taiwan and having learned the way Chinese should be taught rather than the pre- World War II methodology that Stanford had used, I was introduced to some ideas about learning from a professional psychologist (then working for an advertising corporation). He told me how students that were to learn the parts of the brain would be started with a full diagram, let's say of the brain regions labelled on the surfaces of the brain as viewed from the top. The next frame (official teaching machine vocabulary) would be the same diagram but with some degree of "fading," e.g., some name with a letter or two removed that the student would have to fill in. By the end of the process a student would draw the brain outline, mark in the parts, and label the parts. There would be an almost perfect success rate because students were never asked to learn very much at one time. (Contrast that to being given the Chinese character 韤 at the beginning of the third trimester at Stanford and simply being told: "Go learn that by this Friday, along with the other 40 characters for this week." It should have been broken down to 韋、艹、网、and 戍, and some of those characters have their own components that would have earlier helped in learning them.)

I made some substantial progress, after returning from another 3 years in Taiwan, making a "teaching machine" using line drawings and romanization. I learned "C" to do that, and on the old system for Microsoft computers it was not too bad to do everything but the pictures. Then I changed universities and was in an environment that used Macintosh computers. "C" wasn't, it turned out, quite all you had to master. There was a telephone-book-sized volume of subroutines in the Mac system that had to be called to accomplish anything even as simple as putting up one GIF document. Then Macintosh changed their system in major respects after a couple of years. And every year or so all code would have to be readjusted to account for recent improvements. I staggered on ahead, always out of balance. Around 1990 I discovered that on the Mac I could combine WAV files on the fly to make a much better approximation of spoken Chinese than any synthesized Chinese on the market. And, as soon as I had done that, my university shifted everything over to Microsoft systems software and computers. What had taken me a weekend to program on the Mac seemed impossible to do on the IBM computers we were then using. (My main problem was that I could never find out how to see into the WAV files that were composed on the IBM side, whereas they were readily available to inspection on the Mac. Microsoft had hidden them by layering them under a haze of meaningless names somehow. I can't remember how deep into things I could trace them and I don't want to.)

I had spent many years staggering ahead, only just barely able to keep everything together as the systems changed under my feet. Then more intense demands from other directions made it impossible to meet the time demands, so I dropped the whole thing.

Recently I have decided to start all over using JAVA in the hope that it will stay constant and also make my stuff relatively platform independent. Unfortunately my mind seems to be locked in "C" and learning another way to write programs, one that uses a whole new way of putting pieces together, is a big stumbling block. With the present generation of computers memory is no longer a big problem, so I can record and play entire sentences. Illustrations can be photographs instead of line drawings. But I want to redesign how the teaching program moves forward by making progress much less linear and by making review much more flexible and related to the individual user's mistakes and patterns of mistakes.

I got started making and programming computers by buying some perf board, some sockets, some chips, and wire-wrapping a computer to which data was input by pushing fewer than ten spst switches. The instructions came in a book that I think was called EZ 80 or something like that. Then I wired a "Big Board," ancestor of the first computers of several of the non-Mac home computers. So I've done programming on every level from input entirely in hex to some stabs at C++, and from an operating system called PFM burned on an EPROM to recent Mac and Microsoft systems.

I was amused to see Alfred Bester come up as a Psi-Cop character in a TV science fiction series, Babylon 5 I think the name was. Bester, the author, had some interesting ideas and insights.

I never got much support from IT people at my universities, unfortunately. John Stone at Grinnell had a good group of somewhat wild students who would program things on their own and purely for the love of programming. Other places I've been teach more in the abstract and nobody has any idea of how to actually use C or C++ or Objective C to program a Macintosh or even a Lenovo.

It's good to learn of someone who actually programs computers to good effect.P0M (talk) 11:44, 11 February 2014 (UTC)

retro-causality and/or FTL[edit]

There is another problem with the passage you have flagged as needing a citation. The first thing is that if you believe that someone in control of the idler part of the experiment could send a meaningful signal you would have to explain how that person can do anything meaningful because s/he has no choice as to which of the four detector's the next entangled photon will show up at. S/he is watching a random sequence and the person at the other end is watching the same random sequence.

The second consideration is that even in the lab, where I think one experiment was done with the idler detectors separated by several meters, getting a signal from both the idler- and the signal-related detectors to compare would take the amount of time needed to get that information at the speed of light. Without that c-speed communication you don't even know whether your experimental apparatus indicates a coincidence or not.

The experiment was specifically designed to test the idea that experimenters could get which-path information about where a photon "really went" without interacting physically with the photon and spoiling the which-path information in the process. So they figured that they could figure out whether a photon that has participated in an interference pattern went by red path or the blue path to D0 by observing whether its entangled twin ended up in D3 or D4. To avoid the possibility that the idler part of the apparatus sent a light-speed signal to the idler part of the apparatus that told the latter how to behave, they wanted the signal photon to have done whatever it was going to do before the idler photon had "made its move." They got a result that they may have hoped for. The photons that showed up in the signal path that were identified by path information coming from the idler photon did not contribute to an interference pattern. So the information that you are asking for in the citation is already in the description of the experiment in the original article. (Without rereading it I can't be sure that they wrote it clearly enough to let other people in the field figure out what they were doing and why, or whether they stated these things explicitly.)

If we get into why D0 can do things like "deciding" to show photons as though they had come by only one path then we must go into a discussion of entanglement, but that subject needs a whole article just to begin to explain.

I will reword part of the passage that wasn't getting the idea across correctly. Maybe I can drag specific quotations out of the Kim article, but the ideas are there even if they are not packaged for easy export.P0M (talk) 17:17, 14 February 2014 (UTC)

It was almost all there in the article. I had to put in a brief sentence to wrap up the logic. I also found some useful quotations in Greene's Fabric. P0M (talk) 20:43, 14 February 2014 (UTC)

Yes! I'm just back from the library with a copy of The Fabric of the Cosmos. Stigmatella aurantiaca (talk) 20:53, 14 February 2014 (UTC)
I've added a quote from Fabric. Stigmatella aurantiaca (talk) 21:26, 14 February 2014 (UTC)

fascinating extension of Wheeler-type interferometer experiments[edit]

You may find this fascinating. I have yet to work through it in detail.

http://arxiv.org/abs/1304.7469

"Asking photons where have they been"

P0M (talk) 15:42, 19 February 2014 (UTC)

Your GA nomination of Delayed choice quantum eraser[edit]

Hi there, I'm pleased to inform you that I've begun reviewing the article Delayed choice quantum eraser you nominated for GA-status according to the criteria. Time2wait.svg This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by Legobot, on behalf of CycloneIsaac -- CycloneIsaac (talk) 22:20, 20 February 2014 (UTC)

Your GA nomination of Delayed choice quantum eraser[edit]

The article Delayed choice quantum eraser you nominated as a good article has failed Symbol unsupport vote.svg; see Talk:Delayed choice quantum eraser for reasons why the nomination failed. If or when these points have been taken care of, you may apply for a new nomination of the article. Message delivered by Legobot, on behalf of CycloneIsaac -- CycloneIsaac (talk) 22:32, 20 February 2014 (UTC)

Stigmatella aurantiaca, although @CycloneIsaac handled this badly, I think a GA nomination was premature. Contents of GA nominees are supposed to be stable, but this article just came out of an edit war and protection, and I'm not sure the controversy is truly behind us. The content has changed a lot recently and could use a period of quiet copy editing. I suggest waiting a month or two before renominating it. RockMagnetist (talk) 17:03, 21 February 2014 (UTC)

I figured[edit]

I found the discussion on a forum that Cthugha mentioned. In that context DP clearly said that after the "waves" were given circular polarizations they had to be subjected to another manipulation before they would interfere. When, long ago but after he wrote on that forum, I asked him about that very thing he avoided answering my question. I wondered how he was thinking about things, imagining that he had some elaborate rationale. See what he wrote straightforwardly in the forum, I think he was being deliberately evasive with me.

Bummer.P0M (talk) 01:27, 26 February 2014 (UTC)

As for the discussion of the paradox, I think you need a citation. I have not been able to find a peer-reviewed article that discusses it. A paradox is something that is true but doesn't look like it could possibly be true. The reasons that people will give for why "it doesn't look possible" will depend on which interpretation they favor.

The diagram 3-d seems to give incomplete information. When the third mirror is installed, what does it point the path toward? If it points it toward interstellar space a photon might head out and never show up anywhere in the whole history of the universe. It's easier to assume that there is a nice black wall in the way. Also, the diagram leaves the impression that the photon might not bounce off the second beamsplitter. My intuition says that the photon will show up 25% of the time at detector A and 25% of the time at detector B. Is that not true?P0M (talk) 05:33, 26 February 2014 (UTC)

The French Wikipedia article which appears to have been the source of the original figure and text, which I replaced with my own figure and cleaned up, vaguely refers to an article by Kwait et al. without specifically citing the exact article in an inline citation. Looks like I have a bit of research ahead to figure out the source. Stigmatella aurantiaca (talk) 08:16, 26 February 2014 (UTC)
I searched for "Kwait" and tried to hit on the same schematic, but no luck.
If you believe that a photon is either a wave or else a photon (basing yourself on one way of expressing the idea of complementarity) then the paradox is the same as with the Wheeler experiment understanding given by some people (but not Wheeler, ironically): The photon has to "decide" whether it is a particle or a wave at the first beam splitter or at the double-slit diaphragm. However, it has no basis for deciding unless it sends some kind of explorer wave out ahead of itself or does it wrong and then corrects retrocausally after it gets to the barrier mirror, or something else weird happens. If you understand the photon as always being in a superposition of wave and particle until it has to show up on a CCD or something like that, then the photon goes down both paths. If it hits the barrier mirror and some delightful patch of grass out beyond it, it "materializes" there. The other half of the time it doesn't materialize there and instead the part of itself that went down the other path comes to the second beam splitter, splits again (so now we have three copies) and there is a 25% probability of its showing up at one or the other detector (or another patch of the general environment. Actually a better way of saying that is just to note a fifty percent probability for "down in the grass beyond the barrier mirror," plus 25% for the first detector and 25% for whatever is at the other exit from the second beam splitter. There is no "paradox" because the interpretation chosen in the beginning doesn't suggest that there was a decision made that prevented the photon from having a look down both paths.
The Wikipedia article on interpretations of QM has seven or eight different ways of imagining what is going on with a photon or an electron in these situations, and they all might have different ways for being amazed at the consequences or for finding the consequences just what they expected. So I suspect that articles would ideally take account of this kind of thing. Fritjof Capra, a real physicist, wrote a book (The Tao of Physics?)about the similarities between trying to get people to conceptualize things "correctly" in quantum mechanics and in Buddhism. Physicists says his physics isn't terribly hot, and people into Buddhism say his understanding of Buddhism and related subjects is not all that good, but I think that he did a useful thing in alerting us to how much mental furniture we have to throw out when remodelling for living in one of those new thought environments. (There is a "spoof" of Buddhist reasoning called Vimalakirtinirdesasutra, the sutra about the layman called Vimalakirti, that is quite funny but also profound. Various high-ranking figures in the Buddhist hierarchy come to Vimalakirti and stumble all over the vocabulary and logic of their own discipline, and Vimalakirti straightens them all out. The lesson seems to be that even the Buddha's highest disciple can get his foot stuck in his mouth.) P0M (talk) 09:23, 26 February 2014 (UTC)
Either I'm too sleepy or the second article is too frayed to be comprehensible. Maybe what is confusing to me is that I understand about contrafactual conditionals (a nasty problem for some logicians). Arguments about the veracity of a witness who says, "If he had not stabbed at my heart I would not have killed him," are not too hard to assess. But I'm not sure that such issues have anything to do with Bell Inequalities. The article seems to be claiming that Bell tries to make claims about, e.g., momentum as actually measured, but also make claims about the position that would have been there if the momentum had not been measured. For Bohr I'm pretty sure neither position nor momentum where there in the first place, and you can only force one to show up. I can trap an electron in an atomic orbit and then it will have (more or less) a position. But I lose any possibility at that point of measuring a momentum. Alternately, I could have run it into a magnetic field and measured its momentum by how it effected the field system, but then I've changed whatever position it might have had and, moreover, I probably can't even find it.
If memory serves, Bell started by asking what kind of predictions one could make about particles with hidden variables, i.e., with definite positions and momenta that were hidden from us. The hidden variable people could argue that the photon or electron really had a position and a momentum, and the fact that we can only pull out a clear measure of one or the other is just due to the limitations of our measuring processes. Bell's argument was that a truly indeterminate photon or electron (or, actually, a whole string of them) would produce a different kind of statistical picture. So where would he be making assertions about something that was not the fact or that had not been measured and could not be measured as though they could be measured or had been measured?
It seems pretty perverse to me that a ten-page article should cost as much as a substantial hard-bound book. I wonder how much money the writers get for this stuff. I notice that sometimes articles that are available for free are also available for $40 or something on one of those scholarly paper venders. If the object of doing research is to have a better-educated community, then maybe forcing people to pay for articles is counterproductive. In the old days paper journals had to be printed to maintain communications, and they were fairly expensive because there weren't many buyers, the articles collected in one volume involved a lot of type-setting, etc., and the scholars whose papers were published never got any money for their submissions. Maybe I'm just being grumpy. P0M (talk) 10:58, 26 February 2014 (UTC)
(edit conflict) Well, I had been wanting to merge the sections on counterfactual measurement and the Elitzur-Vaidman bomb tester anyway, and there are zillions of references to the bomb tester, Penrose, Hardy's paradox, weak measurements, etc. etc. Stigmatella aurantiaca (talk) 11:06, 26 February 2014 (UTC)
Offer still holds. If you need a $40 article, I can see if I can get it on Saturday after aikido. The authors don't get nutting. Stigmatella aurantiaca (talk) 11:09, 26 February 2014 (UTC)
Sorry about Kwait (sic) Kwiat. Stigmatella aurantiaca (talk) 11:10, 26 February 2014 (UTC)
I had already made the same mistake.
Somebody probably saw:
http://www.thefunisreal.com/tag/quantum-nonlocality/
It leads to something reliable:
http://arxiv.org/pdf/quant-ph/0508102v1.pdf
Cramer says that it "sounds mysterious" but "thefunisreal" makes it into a paradox. It is a "paradox" if you start with the interpretation that says a photon decides at the beam splitter whether it is going in as a wave or as a particle. If you think like Cramer, or if you think that a photon is always a superposition of a wave and a particle, then there is nothing paradoxical about it. P0M (talk) 17:03, 26 February 2014 (UTC)
This article really does have something rather paradoxical:
http://arxiv-web3.library.cornell.edu/abs/1312.7438
I have yet to work through this maze. P0M (talk) 17:17, 26 February 2014 (UTC)
P.S. I too have access to a university library. It is a 20 minute trip, and then there is time to scout the stacks, etc. I would like it if journal documents were on Google Books. Even when it blanks some content in a book, I can usually find out enough to tell whether it would be worth it to go get the book. Thank you for the offer of help. P0M (talk) 17:25, 26 February 2014 (UTC)

Counterfactual definiteness article[edit]

Hi

I'm ready to finish going through my notes for useful footnotes. I am also ready to write to Dr. de Muynck. He has contributed to physics articles, and I've found him to be quite approachable. Before I bother him, I'd like to clear up any inconsistency or unclarity in my own exposition.

Looking back at the original article, it seems to me that much of it is fairly accurate. The problem with it is that it leaves it unclear why counterfactual definiteness has any relevance to real questions in physics. It's like finding a tool in some workman's bag and not having any idea of what it could be used to do.

I can see how Bell's work could be challenged on a theoretical basis for "guesswork," but if the conclusions of the guesswork turn out to be useful that would suggest that it at least has heuristic value. Heisenberg was accused of "guessing" and of "doing magic" to come up with his original rather weird-looking equation, but that didn't make him a dodo.

Please have a look and feel free to edit the draft on the talk page. I can always steer something back in my direction while making it clearer if one of my unclear statements carries you in the wrong direction (unlikely though it may be that you would go wrong).

Thanks. P0M (talk) 19:07, 9 March 2014 (UTC)

POTD notification[edit]

Hi Stigmatella,

Just to let you know that the Featured Picture File:Algol AB movie imaged with the CHARA interferometer - labeled.gif is due to make an appearance as Picture of the Day on June 16, 2014. If you get a chance, you can check and improve the caption at Template:POTD/2014-06-16. Thank you for all of your contributions! — Crisco 1492 (talk) 09:52, 31 May 2014 (UTC)