Talk:Double-slit experiment

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Physics (Rated B-class, Top-importance)
WikiProject icon This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
B-Class article B  This article has been rated as B-Class on the project's quality scale.
 Top  This article has been rated as Top-importance on the project's importance scale.

de Broglie's wave mechanics[edit]

de Broglie's "The double solution theory, a new interpretation of Wave Mechanics" is the precursor of de Broglie pilot-wave theory which Bohm picked up on and is now often referred to as de Broglie-Bohm pilot-wave theory.

de Broglie's Wave Mechanics is the foundation of all of this and it is the theory where wave-particle duality is defined as a physical particle having an associated physical wave in a hidden medium.

de Broglie then extended wave mechanics into the double solution theory. The double solution theory describes the connectivity between the physical particle and its physical wave and also describes the wavefunction of quantum mechanics, hence the name "double solution".

Aephraim Steinberg and Yves Couder are two physicists who are actively working in this realm of quantum mechanics, or in the macroscopic version of this realm of wave-particle duality.

de Broglie's "The double solution theory, a new interpretation of Wave Mechanics" is a valid interpretation of quantum mechanics and what occurs physically in nature in a double slit experiment based upon this interpretation belongs in the "Interpretations of the experiment" section of the double slit experiment article.Mpc755 (talk) 21:28, 1 April 2014 (UTC)

Are you possibly referring to "Introduction à la nouvelle théorie des particules de M. Jean-Pierre Vigier et de ses collaborateurs" with your article title(?) above? If it is an article by de Broglie then you need to cite it explicitly. It isn't mentioned in this article or the article on Louis de Broglie.
Have you seen DParlevliet's critique above? P0M (talk) 21:38, 1 April 2014 (UTC)
I see there is indeed an article, available at: You need to cite things like that. What is the true date of the paper? He died in 1987 and the article was published in Annales de la Fondation Louis de Broglies in that same year. It looks like the original was published in French in 1972, so it might be worthwhile to point out that this "new" interpretation is now about 40 years old.P0M (talk) 21:51, 1 April 2014 (UTC)
I changed the title to "Interpretation of quantum mechanics by the double solution theory" which is the title of the article associated with the pdf which is referred to at the end of the first de Broglie quote. Let me know if this title is still not accurate.Mpc755 (talk) 21:53, 1 April 2014 (UTC)
Changed title to "Double solution theory"Mpc755 (talk) 21:57, 1 April 2014 (UTC)
Probably "De Broglie's double solution theory" would be even better. Dicklyon (talk) 22:04, 1 April 2014 (UTC)
"Relational interpretation" is not "Carlo Rovelli's relational interpretation". If there is a consensus of what the title should be then it should be changed. Thanks for the feedback. Mpc755 (talk) 22:18, 1 April 2014 (UTC)
I'm making it "Wave mechanics" as that is what de Broglie first refers to in the article the first quote is from. Mpc755 (talk) 22:20, 1 April 2014 (UTC)
I changed it back to your previous choice. "Wave mechanics" is way too broad a concept, not representative of de Broglie's interpretation. Dicklyon (talk) 23:31, 1 April 2014 (UTC)
I changed it to "de Broglie's wave mechanics" as the discussion centers around an explanation as to what is occurring in a double slit experiment which de Broglie's wave mechanics is more suited for as it is focused on the physical particle and the associated physical wave in the hidden medium. Mpc755 (talk) 03:40, 2 April 2014 (UTC)

The section is a bit of mess. Here is a good source to help write it better. Probably "pilot wave" would be a more appropriate name, or part of the name. Dicklyon (talk) 23:35, 1 April 2014 (UTC)

Pilot wave is thought of as de Broglie-Bohm pilot-wave theory and has too much baggage. One of the main problems with de Broglie-Bohm pilot-wave theory is that it is nonlocal where de Broglie wave mechanics is local. A problem with de Broglie's pilot-wave is that it is considered a hidden variable theory. There are no such things as hidden variables. Due to conservation of momentum each of the downconverted photon pair can determine the position and momentum of the other based upon their own position and momentum. Entanglement is not a physical or superluminal connection. Entanglement is each of the pair being able to determine the state of the other. Bohm's concept of the wave piloting the particle was described as the radio waves guiding the plane. This is not what the wave of de Broglie wave mechanics is. de Broglie describes the "energetic contact" between the particle and the hidden medium and describes the particle as occupying a very small region of the wave which is in no way describing anything near analogous to radio waves piloting an airplane. What de Broglie is referring to is more correctly described as the particle moving through and displacing the medium. There is also this associated with de Broglie-Bohm pilot-wave theory "The de Broglie–Bohm theory is explicitly nonlocal: the velocity of any one particle depends on the value of the guiding equation, which depends on the whole configuration of the universe." That is not what de Broglie is referring to in terms of the physical wave. Mpc755 (talk) 00:20, 2 April 2014 (UTC)
It appears this section may have been fraudulently created or modified in order to advance a pseudoscientific argument user Mpc755 was trying to promote on the public science discussion website Here's a link to the specific thread, on which the user Mpc755 is presently posting as "cav755" to evade a previous ban from the site. Hopefully this community is readily on guard against cranks further seeking to modify the content here for purposes of misinformation and self-promotion. (talk) 04:03, 2 April 2014 (UTC)
What I have posted here is an explanation of what occurs physically in nature in a double slit experiment according to de Broglie's wave mechanics. I'm not sure why it causes people who consider themselves knowledgeable about physics to go nuts. Mpc755 (talk) 09:33, 2 April 2014 (UTC)
I have to agree with Dicklyon. Basically what is present so far are a few quotations sort of stuck together. It's hard to know what to do with a quotation when you have to figure out who might have said it by taking a look at a footnote. The reader has to guess why you are putting quotations from several sources in sequence.
I think I answered this by adding information within brackets to the quotes. Mpc755 (talk) 14:54, 4 April 2014 (UTC)

Readers would probably benefit from knowing when de Broglie got started on his ideas, when and why he initially gave up on them, and why (in two steps, I guess) he got interested in them again and has had a renewed influence on discussions since the 1970s. P0M (talk) 06:51, 4 April 2014 (UTC)

Mpc755, if you look to the article De Broglie Bohm theory you will find the same, even more extended. So why repeat it in this article? If you have more information, you can add it to that article. Then all information about this theory is in one article and not spead-out over several articles. That is easier for the reader. DParlevliet (talk) 07:21, 4 April 2014 (UTC)
The article starts off with "When in 1923-1924 I had my first ideas about Wave Mechanics...". I don't think this is the place for a history of de Broglie wave mechanics. This is not de Broglie-Bohm theory. I already explained why I am referring to de Broglie's wave mechanics and not de Broglie-Bohm theory. de Broglie's wave mechanics is by de Broglie. de Broglie-Bohm theory is by Bohm. Bohm mistakes the wave function for a physical wave. They are two very different theories and the name of de Broglie-Bohm theory including the name "de Broglie" is very misleading. Mpc755 (talk) 14:54, 4 April 2014 (UTC)

The problem with Mpc755's article as it's presently written (aside from what I've already argued are questionable intentions about making a case for the aether on a science forum), is that his article is lacking in technical details, contains vague and scattered quotes from multiple sources, and it relies mostly on quoting popular science publications rather than transcribing any original or technical papers. Even in the link to de Broglie's original paper, which could certainly be of great academic value, none of the technical arguments therein are outlined and explained, and instead the only part of it contained in this article amounts to a historical quote. I urge all regular contributors here to carefully consider whether Mpc755's contribution contains accurate and relevant scientific info, and not to hesitate to remove anything they don't feel qualifies, or modify the section into a simple link to the original de Broglie article. zz

I just added a technical paper. Mpc755 (talk) 14:54, 4 April 2014 (UTC)

I especially urge the other contributors here to be on their guard for various claims and implications Mpc755 has placed in this section suggesting that de Broglie's model may explain certain measured phenomena in a way that the Copenhagen Interpretation does not. Last I heard, there hasn't been a serious experimental challenge to the Copenhagen Interpretation in the century since it was first introduced. (talk) 13:29, 4 April 2014 (UTC)

The experiment by Aephraim Steinberg allows for a different way of thinking about quantum mechanics. Mpc755 (talk) 14:54, 4 April 2014 (UTC)

I sent an email to Valeriy Sbitnev asking him if my interpretation of his article is accurate. Mpc755 (talk) 14:58, 4 April 2014 (UTC)

Hmmmm, the whole focus of the article is wrong. The article fails to include the standard quantum mechanical derivation of the result, there is only a classical wave physics derivation and then there is a lot of talk about the different intepretations. This is what really should be fixed. I would want my students to study this subject and then be able to answer questions like why you also get interference fringes when photons from the slits are deflected by freely floating mirrors. So, why doesn't the change in the momentum of the mirrors constitute the "which way information" that should wipe out the interference fringes? A well written article would contain enough information to allow the student to at least in principle be able to address this question using the presented mathematical description. The current explanation falls way short of that. Count Iblis (talk) 16:56, 4 April 2014 (UTC)

You are placing a false constraint on de Broglie's wave mechanics by thinking it has the notion of "which way information". If you want to do your students a favor, have them execute the following experiment.
Mpc755 (talk) 17:18, 4 April 2014 (UTC)
User Mpc755, this talk page is for discussing the article, not the subject, and certainly not your own private reasearch. See wp:Talk page guidelines. - DVdm (talk) 17:57, 4 April 2014 (UTC)
I only responded with the experiment I propose to show that "which way information" may just be a misunderstanding of what occurs physically in nature; in response to a comment stating that the de Broglie's wave mechanics section was not dealing with it. I don't think the de Broglie's wave mechanics section of what occurs physically in nature in a double slit experiment is the place to be discussing "which way information", nor do I think we need to be discussing it here. Mpc755 (talk) 19:25, 4 April 2014 (UTC)


Another question: What does "singularity" mean as MPC755 is using it? Is it Singularity (mathematics)? Or is something else possibly intended? How is that different from a soliton?P0M (talk) 00:15, 5 April 2014 (UTC)

de Broglie says a particle is a singularity, in a first approximation. My interpretation of this is that de Broglie isn't exactly sure how the particle exists within its wave. At this time, I don't see how you differentiate it from a nugget. Mpc755 (talk) 02:03, 5 April 2014 (UTC)

I've done some modest cleanup to the section. I make no claims to understanding the material being reported, so I hope others will review and tweak better. Dicklyon (talk) 02:37, 5 April 2014 (UTC)

I'm not sure why the article by Valeriy Sbitnev was removed. It is discussing a particle traveling a Bohmian path through a superfluid physical medium. The wave of Bohmian mechanics is not the wave of de Broglie wave mechanics, however, it is still considered to be a wave which passes through both slits in a double slit experiment while the particle travels through a single slit. Mpc755 (talk) 03:07, 5 April 2014 (UTC)
Thanks for the clean-up. Here are some observations on things that need to be tightened up.
There is still a big problem with the paragraph that starts with: "Aephraim Steinberg's experiments on measuring..." This remark comes out of nowhere. The reader needs to understand that Steinberg was doing measurements that evidently diverged from what standard quantum mechanical theory would predict and found that they were closer to the de Broglie theory-based calculations.
The measurements do not diverge from what standard quantum mechanical theory would predict. From the article, "David Deutsch of the University of Oxford, UK, is not convinced that the experiment has told us anything new about how the universe works. He says that although "it's quite cool to see strange predictions verified", the results could have been obtained simply by "calculating them using a computer and the equations of quantum mechanics"." Simply calculating the equations of quantum mechanics is the problem with quantum mechanics. It's the "shut up and calculate" method of quantum mechanics. It doesn't explain what occurs physically in nature. The experiment performed by Steinberg is showing that you can weakly measure some aspect of the particle and still get an interference pattern.
The part that starts out, "For his part,..." sounds very much like special pleading to me. Who cares what this professor says unless it is well substantiated by experiment and observation. If it is, why do we need his lofty authority to be mentioned?
Because the main interpretation of quantum mechanics, the Copenhagen interpretation, insists you can't ask what occurs physically in nature in physics. You can't ask if the particle travels through one slit or the other. You can't even ask if the particle exists in three dimensional space until it is detected. You have to redefine what a particle is in order to make stuff up. What Steinberg is getting at and what de Broglie insisted was, particles are particles and waves are waves. A particle in a double slit experiment always exists as a particle. It is the hidden medium which waves.
"Steinberg's work stood out because..." strikes me as more of the same. What's worse, it still isn't clear to the average well-informed reader what it is that stood out and why it might be important.
From the article, "The experiment reveals, for example, that a photon detected on the right-hand side of the diffraction pattern is more likely to have emerged from the optical fibre on the right than from the optical fibre on the left. While this knowledge is not forbidden by quantum mechanics, Steinberg says that physicists have been taught that "asking where a photon is before it is detected is somehow immoral". "Little by little, people are asking forbidden questions," says Steinberg, who adds that his team's experiment will "push [physicists] to change how they think about things"." One of the recent popular interpretations of quantum mechanics is Many-worlds. In Many-worlds you can't even say the particle exists in three dimensional space in "our world" until the particle is detected. My interpretation of the point Steinberg is trying to make is that the particle always exists in three dimensional space. To have to state that the particle always exists in three dimensional space in "our world" is nonsense. The particle just exists in three dimensional space. One you understand particles are always particles and waves are always waves and in a double slit experiment the particle travels through a single slit and the associated wave in the hidden medium passes through both most of the nonsense associated with quantum mechanics goes away. Mpc755 (talk) 04:33, 5 April 2014 (UTC)
One of the sources I ran on to was quite refreshingly explicit in saying, basically, "We aren't going to be able to prove anything on a few experiments even if they all go our way. We know that the next experiment may blow us out of the water. But until that happens the results are intriguing enough that we are convinced that we ought to do much more digging in the same place." P0M (talk) 03:32, 5 April 2014 (UTC)


Edit conflict, trying to get back on the track:

O.K., the "double solution theory" paper, p. 3f does have such an assertion. If you are going to provide a section of the double-slit article that does not have the bad effect of mystifying the phenomenon and in so doing put the reader in a confused state, you will need to figure out what this "singularity" is, and also give a clear proof by citation that what you represent in this section is more than your own best guess. To make things a bit more complicated, "singularity" has recently become a buzz word. Who knows what associations the reader will bring to this term?


de Broglie defines "singularity" as a very small region of the wave of high energy concentration. The particle occupies a very small region of the wave.

For me, the particle, precisely located in space at every instant, forms on the v wave a small region of high energy concentration, which may be likened in a first approximation, to a moving singularity. ... This result may be interpreted by noticing that, in the present theory, the particle is defined as a very small region of the wave where the amplitude is very large ... In the double solution theory however, the quantity g is certainly concentrated in a very small region occupied by the particle ... Thusfar, the insertion of the particle in its wave was restrictively defined by stating that the real physical wave must include a small region of very high amplitude, which is the particle. Apart from this singular region, the physical wave is the v wave, of very limited amplitude, and satisfying the usual linear equation.[1]Louis de Broglie

Does it seem to you that de Broglie offers a wavefunction that is a mathematical model for an entity that has mass, energy, and momentum? Does it seem, further, that some small part of the (probably moving) volume of space characterized by that wavefunction itself shows the characteristic of its own "revolving" that gives it an angular frequency and a wave length? (That de Broglie established the proper frequency of the electron is an earlier part of his research upon which the theory currently under discussion must be an elaboration, so that frequency and wave length characteristics are not likely to be subject to debate.) It is how what you call a "nugget" is related to what is basically a Schrödinger wavefunction that needs to be clear. Then the next question would be how that particular model of what is going on would be used to explain the double-slit experiment.


de Broglie's wave function is purely statistical. The wave function of de Broglie's wave mechanics does not move as it does not physically exist. It is the real wave of de Broglie's wave mechanics which is a wave in the hidden medium. de Broglie's "double solution theory" is referring to the two waves. The physical wave guides the particle and the statistical wave function is for making predictions associated with experimental results. Mpc755 (talk) 10:12, 5 April 2014 (UTC)

This result may be interpretated by stating that the current statistical theory considers as spread out in the entire wave, devoid of singularity, that which in reality is totally concentrated in the singularity. It is on account of the foregoing interpretation that I simultaneously considered two distinct solutions of the wave propagation equation connected by eq. (33), one, v, having physical reality, and the other, ψ, normed, and of statistical character. I therefore named this reinterpretation of wave mechanics the double solution theory. By distinction of the two waves v and ψ, the mystery of the double character, subjective and objective, of the wave in the usual theory, vanishes, and one no longer has to give a simple probability representation the strange property of creating observable phenomena.[1]Louis de Broglie

To use the water-droplet experiment as an analogy, there seems to be one equation that governs the behavior of the "support apparatus" surrounding the suspended droplet, and another equation that characterizes the droplet itself.


There is one equation representing the connectivity between the particle and the physical wave and another equation giving statistical information. One equation represents what is occurring physically in nature and the other allows for making predictions of expected results from experiments. Mpc755 (talk) 10:12, 5 April 2014 (UTC)

However, since the publication of Schr ̈odinger’s works in 1926, it became customary to only consider the ψ wave, of arbitrarily normed amplitude. But this wave cannot be considered as a physical wave, first because the amplitude of a physical wave has a well determined value, and cannot be arbitrarily normed, and because if ψ 1 and ψ 2 are two particular normed solutions of the linear ψ wave, the ψ 1 + ψ 2 sum of these two solutions is not a normed solution. In other words, the normed ψ wave is not endowed with the superposition property characteristic of the physical wave solutions of a linear propagation equation. One is therefore led to consider the ψ wave as a probability representation, a simple prediction instrument, permitting a forecast of the possible measurement results of physical quantities belonging to a particle or to an ensemble of particles. It is however impossible for a simple probability representation to create physical phenomena such as the local observation of a particle, or to impose definite values to energies of atomic stationary states. Objective reality only, may give such effects, and a probability representation has no such character[1]Louis de Broglie

Beyond this basic level of understanding, the revived de Broglie explanation will face the difficulty that there are apparently no objective measures possible that would allow one to predict what trajectory an electron would take from the region of the double-slit diaphragm. Will this explanation be able to offer anything other than a "just believe me" substantiation?
The uncertainty principle still applies. The uncertainty is that you can not know where the particle exists within its wave without detecting it.
Right now the section is not clear.It is not good enough to write something that contains only true statements (assuming that the truth of any statement can be established unless it is just something of the sort "Smith said," when Smith or recording of Smith's speech support the assertion). Misunderstandings will surely emerge from an inadequately structured essay, and "You failed to guess what I was really getting at" is not an adequate defense of such an essay. P0M (talk) 03:12, 5 April 2014 (UTC)
I agree, it's not clear. Please do what you can... Dicklyon (talk) 03:51, 5 April 2014 (UTC)
If you are referring to the section discussing the article by Valeriy Sbitnev, it is included because it is the first article I have found which relates the wave of wave-particle duality with the hidden medium, in this case described as the superfluid physical vacuum. I think it is important information as it is stating that it is the "window glass" described by Robert Laughlin which waves. The article does refer to the Bohmian interpretation of the wave which is different than the de Broglie physical wave I have been describing and does cause confusion. Mpc755 (talk) 04:06, 5 April 2014 (UTC)

The article by Valeriy Sbitnev describes the particle as moving through the superfluid physical vacuum causing it to wave. This is the definition of wave-particle duality as defined by de Broglie's wave mechanics. Mpc755 (talk) 05:07, 5 April 2014 (UTC)

This last paragraph you added is not even sensibly formatted. It's hard to see what it is supposed to mean, and the interpretation is unsourced. The referenced paper does not even appear to be peer reviewed. I don't quite see the relation to the two-slit experiment anyway. I expect it will need to be removed. Dicklyon (talk)
In a double slit experiment the particle travels through a single slit and the associated wave in the superfluid physical vacuum passes through both. Mpc755 (talk) 05:08, 5 April 2014 (UTC)
Your idiosyncratic interpretation of the physical reality is of little relevance on this talk page. Dicklyon (talk) 05:14, 5 April 2014 (UTC)
Let me rephrase that... The waves on the oil surface and the interference pattern created by them, are akin to the de Broglie pilot-wave. And the oil in the bath plays the role of the superfluid physical vacuum for the droplet that moves on this surface. Mpc755 (talk) 15:11, 5 April 2014 (UTC)
I have reverted your last bit. See edit summary. - DVdm (talk) 15:29, 5 April 2014 (UTC)


I asked Valeriy Sbitnev to review what I had written and the following is his response.

As for the experiment of Yves Couder and co-workers, the droplets bounce on the oil surface which undergoes to a very small vertical vibration inducing subcritical Faraday waves. What does it mean? Amplitude of the subcritical waves is so small that we can not see visually these waves. But if we increase slightly vibrations of a basin with the oil the waves exhibits themselves visually. That is, the vibrations are supported near the supercritical bifurcation of emergence of the Faraday waves.

The oil surface gets high sensitivity in the vicinity of the supercritical bifurcation on any touching to it. The closer the bifurcation point the higher the sensitivity. It means, that as soon as the droplet touches the surface, it induces on the surface nondecaying Faraday oscillations. These oscillations create the interference with each other. In turn, it provides an optimal path for the droplet that is moving on this surface.

The waves on the oil surface and the interference pattern created by them, are akin to the de Broglie pilot-wave. And the oil in the bath plays a role of aether for the droplet that moves on this surface.

It is my vision of the de Broglie-Bohm theory. As I see, it is in good accordance with your vision.

What Valeriy Sbitnev writes to you is entirely irrelevant.
Also, please have a careful look at wp:BRD. You made a bold edit ([1]), I reverted ([2]) and started discussing here ([3]). The idea is that you discuss and not revert again as you did just now ([4]). - DVdm (talk) 15:46, 5 April 2014 (UTC)
In the revision history of the main Double-slit_experiment page you said, "No evidence that this is directly related to the article". It is directly related to the article as the article is written by Valeriy Sbitnev and he is saying the walking droplets and their associated waves are akin to de Broglie's pilot-wave and he uses the term "aether" to refer to the hidden medium. All I did was replace "aether" with "superfluid physical vacuum" so as not to have people freak out over the use of the word "aether" and switch "a" to "the" for readability. Mpc755 (talk) 16:04, 5 April 2014 (UTC)
Please have a careful look at wp:SYNTH. - DVdm (talk) 17:00, 5 April 2014 (UTC)
Couder discovered a macroscopic pilot wave system in the form of walking droplets. Sbitnev relates that to particles moving through the aether. They are both describing physical phenomenon having to do with pilot-waves. They are both describing the same physical phenomenon. Sbitnev extrapolates the walking droplets behavior to particles having associated pilot waves in the aether. Mpc755 (talk) 17:15, 5 April 2014 (UTC)
Please have a careful look at wp:FRINGE and wp:UNDUE. - DVdm (talk) 17:37, 5 April 2014 (UTC)
The article by Valeriy Sbitnev is under consideration for publication in J. Fluid Mech. Can we wait to see if it is published before removing it? In general, it is a very good explanation of de Broglie's pilot wave. I added "Under consideration for publication in J. Fluid Mech." to the article reference. Mpc755 (talk) 17:55, 5 April 2014 (UTC)
Seems to be putting the cart before the horse there, Mpc755. Anything can be "under consideration for publication" by anything. I could submit a crayon drawing to Nature and it'll be "under consideration for publication" until they turn me down. Why not wait until it actually gets published before making arguments about whether or not it should be included. (I have removed the "under consideration" language, as that inappropriately associated J. Fluid Mech with something that they have not decided to publish.) 0x0077BE [talk/contrib] 18:54, 5 April 2014 (UTC)

Again, as I wrote above, Mpc755 specifically added the "info" on de Broglie's outdated theory because he's trying to argue for a classical Newtonian universe that evilly conspires to look random. Mpc755 started a discussion at as user "cav755", where he's promoting himself as a revolutionary genius who's finally bringing back the good old aether theory. Notice how the de Broglie section contains little relevant information other than speculative quotes taken out of context in order to favour the old deterministic point of view? Notice how it doesn't even contain a single equation or anything technical- after all, why would the guy who wrote the section bother to learn mathematics and real science when he's already convinced himself that probabilistic quantum mechanics is fundamentally wrong?

The de Broglie section takes up a vastly disproportionate amount of space, in an otherwise important article that could have been useful to students and laymen who come here to learn about real science, instead of the preachings of a crank who thinks he knows more about reality than all the greats of the past 100 years, and doesn't have any technical background. The section should be deleted outright because of its lack of useful information, its misleading out of context quotes, its disproportionate volume in relation to the rest of the article (in direct violation of Wikipedia's fringe policies, as I understand them), and the fact that it was really just placed here so a layman fringe crank could promote old 19th century notions of aether. The section should be deleted, and if Mpc755 or any other incarnation of his accounts tries once again to put it back or revert it without debate against the spirit of Wikipedia community policies, he should be permanently banned from being able to do so. What he's doing here is equivalent to scribbling notes into library biology textbooks about how creationism must be the only possible explanation for life and who they should listen to in order to understand why.

Oh and Mpc755, if you once again edit my comments in any way so as to stick your response into the middle and mess up my formatting, I'm going to revert your edit. (talk) 19:43, 8 April 2014 (UTC)

I think a two line summary would be just about wp:DUE. The remainder of the section reads like a schoolbook example of extreme wp:SYNTH - DVdm (talk) 20:23, 8 April 2014 (UTC)
The section in its present form violates a whole bunch of Wikipedia policies, on top of being written in terribly poor taste. I agree that it might be nice to make a little mention of de Broglie, especially since his original wave mechanics ideas helped give birth to the Schrodinger approach to quantum mechanics. I agree that a couple of sentences and a link to the main article would be all that's relevant here, and I don't understand why such an important and likely widely-perused article has sat here being repeatedly vandalized by the same user, repeatedly reverted to the way he wants it without discussion, and so on. What are you guys waiting for, exactly? If one crank can cause so much trouble and get away with it for more than a week, just wait until the dozens of others over at alone figure out it's open season on Wikipedia. (talk) 20:48, 8 April 2014 (UTC)
I 'm a bit baffled by this too, and I already mentioned this at Wikipedia talk:WikiProject Physics#Heads up at Double-slit experiment. I am not going to touch the article in this respect because it would get me blocked for edit-warring in no-time. So, frankly, I'm somewhat waiting for someone to use a nine-foot pole and do the job that needs to be done. - DVdm (talk) 21:01, 8 April 2014 (UTC)
Done. I agree with DVdm, it is WP:SYNTH and WP:UNDUE. If someone wants to add back a few lines of appropriate and sourced content on whatever in that mess was relevant to the article, be my guest. --ChetvornoTALK 21:54, 8 April 2014 (UTC)
This is not a section on weak measurement. This is a section on de Broglie wave mechanics. Steinberg says his results match those of pilot-wave theory. The MIT experiment specifically says, "Whatever the case may be in quantum mechanics, the statistics are an incomplete description of our fluid system and emerge from an underlying pilot-wave dynamics". This is one of the main points of this section. Both Steinberg and the MIT professors are saying quantum mechanics is statistical and incomplete and their experiments are better represented by pilot-wave dynamics. In the video it goes on to say, "This physical picture is remarkably similar to an early model of quantum dynamics proposed by Louis de Broglie..." They are saying they are seeing de Broglie's wave mechanics in the walking droplets. They have evidence of de Broglie's wave mechanics. Mpc755 (talk) 22:24, 8 April 2014 (UTC)
Aaaaaaand it seems some crazy person has put it back once again. (talk) 22:19, 8 April 2014 (UTC)
de Broglie-Bohm Theory was a theory by Bohm where the wave function is the physical wave. This is completely different than de Broglie wave mechanics, double solution theory or de Broglie pilot-wave theory. In de Broglie's theories the wave is physical and in "energetic contact" with the particle. The particle occupies a very small region of the wave. In de Brolglie's double solution theory there is the physical wave and there is the wave function which is purely statistical. In Bohmian mechanics, which is the de Broglie-Bohm theory, the wave function is somehow thought to be physical. de Broglie wave mechanics and de Broglie-Bohm theory are two very different theories. de Broglie-Bohm theory is incorrectly named as it is really Bohmian mechanics which de Broglie did not agree with. Mpc755 (talk) 22:42, 8 April 2014 (UTC)
@Mpc755 - Then you need a reliable, secondary source that describes th de Broglie wave mechanics interpretation of quantum mechanics. It would help if the source also mentions how it relates to the double-slit experiment. As it is right now, the section is a synthesis of a primary source (de Broglie quotes) and a few tangential or loosely connected statements from other secondary sources. For example, connecting Laughlin's glass to de Broglie's pilot wave is pure synthesis on your part - you need a secondary source that draws that connection to include here. Also, only in the first ref to the weak measurement experiment does it mention a pilot-wave theory but even then it doesn't indicate whether it is talking about the de Broglie-Bohm theory or your de Broglie wave mechanics. --FyzixFighter (talk) 23:03, 8 April 2014 (UTC)
From the MIT video, "Whatever the case may be in quantum mechanics, the statistics are an incomplete description of our fluid system and emerge from an underlying pilot-wave dynamics. This physical picture is remarkably similar to an early model of quantum dynamics proposed by Louis de Broglie..." The early model of quantum dynamics proposed by Louis de Broglie is de Broglie's wave mechanics. Also from the video, at the 2:10 mark, the MIT researches refer to what they are seeing as an "Exposed Variable Theory". de Broglie's pilot-wave theory is considered a hidden variables theory. The MIT researches are saying what they witnessed is not a hidden variable theory. The MIT researches are saying we need to go back to the beginning, which is de Broglie's wave mechanics. Mpc755 (talk) 00:09, 9 April 2014 (UTC)
Being "similar" does not mean it confirms the theory, and the video is not peer-reviewed. More importantly, this article is not about recent developments in interpretations of QM. Mpc755, your long entry, with quotes, is not appropriate for this article. Why don't you add it to Interpretations of quantum mechanics? --ChetvornoTALK 02:56, 9 April 2014 (UTC)
de Broglie's wave mechanics is the only explanation where there is a physical particle which travels through a single slit and an associated physical wave which passes through both. If the de Broglie's wave mechanics section only has a description of de Broglie's wave mechanics it gets removed for not having any supporting evidence. If I then add supporting evidence you remove it for not simply discussing de Broglie's wave mechanics. Mpc755 (talk) 03:08, 9 April 2014 (UTC)
Mpc755, the consensus on this page seems to be against your addition. You need to stop pushing it. --ChetvornoTALK 03:00, 9 April 2014 (UTC)
The consensus thinks a probability wave function physically exists. The consensus doesn't know the difference between de Broglie's wave mechanics and de Broglie-Bohm pilot-wave theory. The consensus can't explain what occurs physically in nature in a double slit experiment. Mpc755 (talk) 03:08, 9 April 2014 (UTC)
Nevertheless, WP:CONSENSUS is how issues are decided on Wikipedia. You could write your theory on Wikibooks. They have no requirement for sources, you could write a whole book about it. Please read WP:EDIT WAR. If you keep edit-warring, I will report you to an administrator, and you could get blocked. --ChetvornoTALK 04:53, 9 April 2014 (UTC)
Just FYI - there is already a report at WP:ANEW since he blew past 3RR in less than two hours today. --FyzixFighter (talk) 05:02, 9 April 2014 (UTC)
...aaand he got a 24 hour block. --ChetvornoTALK 06:16, 9 April 2014 (UTC)

Added a short summary of de Broglie's wave mechanics with a link to where it is described in de Broglie's important theories. Mpc755 (talk) 07:30, 10 April 2014 (UTC)

I have removed your wp:UNSOURCED content, pointing to the same freshly added wp:UNDUE and wp:SYNTH content in another article Louis de Broglie. - DVdm (talk) 07:47, 10 April 2014 (UTC)
I have reduced the de Broglie's wave mechanics interpretation of what occurs physically in nature in a double slit experiment to its most basic description. Mpc755 (talk) 08:34, 10 April 2014 (UTC)
Reverted. User Mpc755 is blocked again, now for 5 days. - DVdm (talk) 08:55, 10 April 2014 (UTC)
I'm making a scientific prediction here that yet more junk science vandalism will occur once the strait jacket comes off again, and the corresponding ban lengths will asymptote to N^{5/2}, where N is the number of violations. (talk) 17:12, 10 April 2014 (UTC)
Note that it's not a ban, but a block. Check out the difference. - DVdm (talk) 17:21, 10 April 2014 (UTC)

Unsourced content[edit]

User DParlevliet has been adding the same unsourced comment 3 times now:

  1. [5] adding unsourced content
  2. [6] re-adding same content with a source not backing the content
  3. [7] re-adding same content with a source not backing the content, made in logged out mode as (talk · contribs)

I checked the cited source (Brian Greene, The fabric of the cosmos chapter 5 - Propability and laws of physics). In my version (ISBN 0-375-41288-3), chapter 5 is The frozen river and it is about Time. It never mentions anything even remotely related to the added content. Does anyone have another version of this book? - DVdm (talk) 09:39, 21 April 2014 (UTC)

Sorry, my error, it is chapter 4. My page 107, but I have a Dutch version which probably will be different. DParlevliet (talk) 09:57, 21 April 2014 (UTC)
The double-slit experiment is indeed implictly mentioned in chapter 4 (see also figure 4.4). Probability and the Laws of Physics is a section between pages 88 and 92. Can you cite the passage (in Dutch) that you think supports the content you want to add? - DVdm (talk) 10:09, 21 April 2014 (UTC)
Probably the figures has the same numbers. Fig 4-4 shows the double slit with electrons. The propability text is just above figure 4-5. However you still did not tell what you dispute.DParlevliet (talk) 11:31, 21 April 2014 (UTC)
Ok, got it. In my version we do find something that directly supports your text. It's on page 90, a few paragraphs under figure 4.5. I will re-insert your text with this source: [1]
By the way, I have taken the ISBN 0-307-42853-2 version that allows direct verification. - DVdm (talk) 19:11, 21 April 2014 (UTC)

Please discuss changes[edit]

Dparlevliet, I disagree with your latest change. The way you have phrased it is correct only for a monochromatic source. Your previous change, while not incorrect, just deleted some careful phrasing. I recognize that English is not your primary language, but if you need help with grammar, then let's work on it here.

OK? --Ancheta Wis   (talk | contribs) 13:06, 24 April 2014 (UTC)

The first change is correct too, I think, but shorter so more clear. Too much detailed, formal text is confusing for the average reader, for which Wikipedia is intended. What do you miss in the first change?. The second change: the double slit always uses a monochromatic source, also the former text. Edits of my English are always appreciated. DParlevliet (talk) 13:24, 24 April 2014 (UTC)
Re "the average reader, for which Wikipedia is intended": I don't think that's entirely correct—see WP:TECHNICAL. In a nutshell: "Strive to make each part of every article as understandable as possible to the widest audience of readers who are likely to be interested in that material." Arguably the average reader is not interested in this subject. See also WP:EXPLAINLEAD, from the same guideline, explaining that in the lead—i.e. before the first section—broad readership can indeed benefit from less technical jargon.

Also note that making back/forth changes to the article before consensus is reached on the talk page might be a bad idea. It's better to discuss possibly problematic changes before making them, specially if someone proposed to "work on it here." - DVdm (talk) 13:46, 24 April 2014 (UTC)

I just changed it to be more clear for "the widest audience of readers" and did not made any problematic change. My text explains the same as the former (my first change). Please be more specific what could be wrong. DParlevliet (talk) 14:37, 24 April 2014 (UTC)
I was talking in general, reacting to that average reader comment. I'll leave the specifics for Ancheta Wis. - DVdm (talk) 14:40, 24 April 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── " So this experiment shows that photons has wave-particle duality." This sentence could be a summary, but does not follow from the preceding text, and the verb is ungrammatical. It would be better to simply strike the sentence as gratuitous commentary. But that's not the end of it. I call the cooperative nature of the wiki the wiki-action, where the sum of the changes produces an amazing result. It helps wiki-action to 'go along with the flow'. Instead, I see semi-combative responses, which slows down the wiki-action, as it elicits defensive behavior all the way around, rather than encouragement.

The term 'photon' ... I could go on, but this is a lot of work for one sentence that needs to go. --Ancheta Wis   (talk | contribs) 15:11, 24 April 2014 (UTC)

I will look to it. But the second part I don't understand. What is the striped text? Which sentence needs to go? DParlevliet (talk) 17:14, 24 April 2014 (UTC)
The striped text is due to markup. Perhaps you might simply ignore it.
I fixed the omission of 'monochromatic light' already. How about sitting back a bit (i.e., take a rest). There are many editors who might contribute as well. --Ancheta Wis   (talk | contribs) 17:25, 24 April 2014 (UTC)
I had not yet seen you changes. They are fine for me. The wave-particle is also mentioned later on. I just wanted to make clear that not only the double slit, but also the single slit shows the wave properties. The double slit is just another, more visible interference.DParlevliet (talk) 08:48, 25 April 2014 (UTC)


I must reiterate the above request that DParlevliet discuss his changes here before making changes in the article. I just had a look at the latest change, and the syntax is not correct. The level of DParlevliet's English writing has been a constant problem since he began his editing here. Even knowing how Feynman set his explanation up, I can't really follow the English. When I correct it to what should have been written to make proper English out of it, I see that it makes some statements that are only dogmatic in form, and that stand as isolated utterances. The reader has to guess how one get to sentence n+1 from sentence n. There must be some connection, one would expect, but what is it?

Spirit of collegiality issues aside, the way the article stands now it has a block of incomprehensible text to stymie the progress of any reader. That result, regardless of whether DParlevliet has yet been led to understand what his syntax problems are, is not one that serves the interests of Wikipedia or its readership.

A more colleague-friendly way to take up a change you think is needed would be to state on the discussion page first what you think is wrong with the present text and see whether other people can understand and accept your critique.

I think it must also be kept in mind that this spinning arrow "clock" that Feynman used in his presentation to non-physicists is a huge simplification. On top of that, if I remember correctly, he posits a detector in or near one of the slits that could detect a photon but let it pass on through. Unless I've missed something, there is no such detector. The fact is that how a photon is judged to have passed through the double-slit apparatus always involves a human construction, placed on observables, that pretends to tell us about unobservables. Also we need to remember that the whole discussion is a huge simplification of [quantum electrodynamics]. So if we use the Feynman model to discuss the double-slit experiment, we must be careful not to claim too much for it. P0M (talk) 02:03, 21 May 2014 (UTC)

You need to source your work also, DParlevliet. You have been warned about this on this page before. You replaced a version which had 5 sources with your own completely unsourced version, and then you reverted when I removed it for lack of sources. Please read WP:VERIFIABILITY. "Any material lacking a reliable source directly supporting it may be removed and should not be replaced without an inline citation to a reliable source." You can be blocked for edit-warring. --ChetvornoTALK 03:11, 21 May 2014 (UTC)
First of all, only part of the text is mine. All essential was there before. I only added how Feynman started with the idea of placing detectors at the slits which would remove the interference, with the explanation from his well known lectures. If language is not right, then improve. If something is wrong, then improve or explain here. If there is lack of references, then place "citations needed" where needed. That is wiki-principle, in stead of deleting all.DParlevliet (talk) 08:32, 21 May 2014 (UTC)
I have reverted again ([8]) and gave an edit warring warning on your talk page ([9]). - DVdm (talk) 10:47, 21 May 2014 (UTC)
DParlevliet, besides your English, which is bad enough to make your argument incomprehensible to many readers, your discussion of Feynman's path integral formulation is not really relevant to the issue. The argument you are trying to make is that to create an interference pattern, you need a contribution from both slits; the particle (or wavefunction) needs to be able to reach the screen from both slits. And any detector capable of giving "which path" information will prevent the particle from reaching the screen from that slit. The last statement is not necessarily true. Neither the DParlevliet version nor the old version really addresses the issue of "which path" information. --ChetvornoTALK 13:33, 21 May 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── DParlevliet, it's time to propose your changes on the talk page first, and not in the article. It's more respectful to the other editors. If the formal English that is needed for the article is getting in your way, then please put your version on the talk page or in a draft. But please work it out by yourself, or with others, before posting it to the article page, using the consensus of the community of editors of this article. Coöperation is no small thing. The small things add up to a larger impression that gets in the way of a better article. --Ancheta Wis   (talk | contribs) 14:16, 21 May 2014 (UTC)

Edits must be discussed first when they are controversial, but what I wrote was just the standard explanation of Feynman's detectors, which was already mentioned in the article. See above, there is no explanation in detail about what is wrong, anyway nothing which according Wiki-rules justify deleting. I have written a lot in Wikipedia and only get small adjustments of language, so that cannot be that bad. DParlevliet (talk) 14:44, 21 May 2014 (UTC)

Note - blocked for a week. Meanwhile DParlevliet reverted again to the faulty version. I guess that this edit can safely be undone. - DVdm (talk) 17:51, 21 May 2014 (UTC)

David Deutsch[edit]

David Deutsch says in his book The Fabric of Reality that the Double-slit experiment is a proof for those who argue that Multiverse is real.

The article says nothing regarding the Many-worlds interpretation. May I inquiry why not?

Kartasto (talk) 14:51, 14 July 2014 (UTC)

Please give a page number and a quote to back this up. --Ancheta Wis   (talk | contribs) 15:56, 14 July 2014 (UTC)
The Fabric of the reality, whole chapter 2. Here:[10] is more I suppose...

Kartasto (talk) 16:05, 14 July 2014 (UTC)

Single photon experiments[edit]

An article on Single photon experiments[1] gives a critique of a proposed experiment, to revisit whether a linearly polarized photon state must be a superposition of a pair of circularly polarized photons or not. --Ancheta Wis   (talk | contribs) 02:33, 27 July 2014 (UTC)

  1. ^ Chris Lee (July 26, 2014) Ars Technica