Talk:Matter wave/Archive 1

Fermi Wavelength
I notice that there is not an article in Wikipedia about the Fermi wavelength, but thinking about it maybe it is not significant enough to warrant its own article. Perhaps, instead, a section within this article? Casey boy (talk) 10:33, 17 May 2010 (UTC)

Ordering of Sections
The section on the Spatial Zeno effect should be moved to below the section on the experimental confirmation of the hypothesis. The Zeno effect is a very specific, highly technical example of the hypothesis and is probably meaningless to most people who visit this page. The subjects of the experimental confirmation sections are more accessible. --Mckinlayr 04:19, 4 June 2007 (UTC)

Linked 'de Broglie Wavelength' to here
This is what his discovery is commonly called - makes more sense if it redirects here.

--Blinken 11:40, 27 Apr 2005 (UTC)

Remove added text
I removed the following text added anonymously:
 * According to de Broglie, an electron bound to the nucleus behaves like a standing wave, such as the vibration of a plucked guitar string. Certain points along the wave do not move at all, these points are known as nodes. There is a node at each end and sometimes between the ends. The greater the frequency of vibration, the greater the number of notes and the shorter the wavelength. 


 * De Broglie reasoned that if an electron does behave like a standing wavfe in the hydrogen atom, the length of the wave must fit the circumference of the orbit exactly. Otherwise the wave would partially cancel itself out on each successive orbit. Eventually the amplitude of the wave would be reduced to zero, and the wave would not exist.

My reason for removal is two-fold: 1) its in the wrong place in the article, it should appear later, 2) This was not de Broglie's idea; it was proposed considerably earlier, by Bohr .. the Bohr model of the atom aka the Bohr-Sommerfeld model. It was a semi-classical theory, with action-angle variables, and a nasty perturbation theory. Google says Bohr propsed this in 1913. See wolfram article linas 03:48, 27 November 2005 (UTC)

removed section on pronunciation of "de Broglie"
It belongs in the article about him, not here. Meeve 22:30, 7 December 2005 (UTC)

Waves of what???
which kind & of what nature exactly these waves are???

i read in some books that it is waves of probability, but actually I didn't understand this well.

I wish someone inform me about it.

thanks..
 * In 1923 this was not known yet - I think de Broglie assumed the particles themselves exhibited wave properties. Currently, it is understood that it is the quantum mechanical wave function that oscillates. Which is perhaps just another way of saying the same thing, since a particles wave function contains all there is to know about a particle's state. You'll find more information in Introduction to quantum mechanics and articles linked from there. Shinobu 14:50, 3 December 2006 (UTC)

Removed line "this equation is essentially wrong"
If this user thinks he has falsified a Nobel Prize-winning theory he should at least post it using his user name. A particle with zero velocity shouldn't be expected to show any wave-like behaviour; if it doesn't propagate, it isn't a wave. Someone more knowledgable than I may be able to explain this better. Shayno 12:34, 12 October 2006 (UTC)
 * I don't know what the anon said, but I think I should at least point out that a particle with zero velocity (say, an electron in a constant potential) tends to sort of spread out over space. Compare the lowest mode in the infinite box, which is just more dense at the center, but not really localized, or the lowest mode in the continuously repeating box, which is sort of everywhere, if my memory serves me right. None of this would falsify this theory. The wavelength just goes to infinity for stationary particles, as you would expect. Shinobu 14:33, 3 December 2006 (UTC)

Bogus
This is deBogus! There seems to be something wrong with the frequency formula. 128.250.50.92 07:20, 16 October 2006 (UTC) Shayno 18:59, 31 October 2006 (UTC): deBogus no longer! Some anonymous user deleted 'em. Accident? Halloween prank? Who knows?!

Caps
"de Broglie hypothesis": caps inconsistent on the d and the h. Someone should check what is common usage in English and fix it. Shinobu 19:53, 3 December 2006 (UTC)


 * It should always be "de Broglie hypothesis". It should be consistent now.  &mdash; Laura Scudder &#9742; 21:48, 3 December 2006 (UTC)

Hypothesis?
Why is the word "hypothesis" in the article title? Is that what it's commonly called for some reason? If not, the name (and perhaps the text) should be changed to reflect the fact that everything in the article is extremely well-verified. -- SCZenz 21:03, 22 January 2007 (UTC)
 * I think it's typically called the "de Broglie hypothesis" because it was just a hypothesis at the time that de Broglie proposed it. It was experimentally confirmed in 1927 by the famous Davisson-Germer experiment, which demonstrated electron diffraction.


 * However, so far as I know there's no general rule for when you use the word "hypothesis" in physics (as opposed to "law", "theory", etc.) In my own rough estimation, a "law" is a single idea about the relationship between quantities (e.g., Newton's law of gravitation relating gravitational force to mass and the inverse square of distance), and a hypothesis is a single idea (not necessarily an equation) like "all matter has a wave-like nature", and a theory is a collection of laws and hypothesis purporting to explain some phenomenon.  But there's no strict rules, and usually the names are simply historical artifacts (e.g., someone called it the "de Broglie hypothesis" and the name stuck.)  All these terms can refer to ideas both before and after experimental confirmation -- the notion of a hypothesis getting "promoted" to a law after verification is generally not correct. --Tim314 15:08, 23 January 2007 (UTC)

There is a mistake in the Relativistic Frequency. Should have (gamma-1) not gamma —Preceding unsigned comment added by 201.203.168.138 (talk) 19:01, 21 September 2010 (UTC)

There may be a mistake in the equations that were written in this page
We can get Debroglie relation from the the equation of Einstein and Plank: $$E=hf=pc$$ Where E is the energy possesed by an arbitrary photon relative to an intertial frame of reference, h is planck constant, f is its frequency in that frame. $$p=\frac{hf}{c}=\frac{h}{\lambda}$$ Where $$\lambda$$ is the wavelength of the photon. We can then postulate that every moving body will have certain wavelength. The equation is experimentally proven to be correct for every body with non-zero rest mass. Similarly, $$f=\frac{pc}{h}=\frac{mc^2}{h}$$ Where m is the relativistic mass of that photon. We can again postulate that every body with non-zero rest mass will have the frequency showing on the above equation. Since $$v_p =f \lambda$$ where $$v_p$$ is the phase velocity. $$v_p=\frac{c^2}{v}$$ Apparently, frequency of a body with non-zero rest mass is not directly proportional to its kinetic energy but its total energy or total relativistic mass. Thljcl 14:23, 25 March 2007 (UTC)


 * The problem with your math is at $$pc = mc^2$$. I assume you got at it by setting $$E = pc$$ equal to $$E=mc^2$$, but the first is the total energy of a massless particle, the second the total energy of a massive particle at rest.
 * Part of what was so unexpected about de Broglie's hypothesis was that he took equations for a massless particle and played with them until found something new that's true for massive particles. Unfortunately, it doesn't usually work that way.  &mdash; Laura Scudder &#9742; 21:55, 25 March 2007 (UTC)
 * For a particle with non-zero rest mass, when its momentum is zero relative to an inertial frame of reference, we find that
 * $$E=m_0c^2$$
 * Where E is the total energy, $$m_0$$is the rest mass of the particle, c is the speed of light in vacuum. When it possesses momentum in the same frame,
 * $$E = \sqrt{m_0^2c^4 + p^2c^2}$$$$= \gamma m_0c^2$$
 * $$p=\gamma m_0 v$$
 * $$\gamma=\; \frac{1}{\sqrt{1-\frac{v^2}{c^2}}} $$
 * When v=0, $$\gamma$$=1,

$$E=m_0\;c^2$$ Classically, we define momentum as a product of mass and velocity. We can still use this definition. However,mass of a particular body is no longer a constant but is frame-dependent and is a function of its velocity. Whatever frame it is, its rest mass will be the same. Therefore, many or most scientists today would like to regard rest mass is the only definition of mass because variable mass may lead to a confusion. For me, I would still use both frame-dependent mass and invariant mass. In my maths, m always means relativistic mass. I will use $$m_0$$ denotes rest mass. Therefore,
 * $$E=mc^2$$
 * $$E_k\;=(m-m_0)c^2=(\gamma - 1)m_0\;c^2$$
 * Where $$E_k$$ denotes kinetic energy. For a particle with zero rest mass such as photon, its kinetic energy is ill-defined. The expression $$E=mc^2$$ is different from $$E_0\;=m_0\;c^2$$ where $$E_0$$ is a particle rest energy. I use E to denotes total energy. Wherever there's energy, there's always a certain amount of mass associate with it, though there may not be the rest energy. Certainly, photon has zero rest mass. It carries both momentum and energy.
 * $$p=mc$$
 * $$E=hf=mc^2=pc$$

Since many people dislike the term of relativistic mass, there's still an another way to derive the expression $$E=pc$$. That is from $$E=\sqrt{m_0^2c^4+p^2c^2}$$ Let $$m_0=0$$,
 * $$E=pc$$
 * Therefore, the derivation of De Broglie is correct with his own postulate. He postulated that all body with non-zero rest mass also have wave-particle duality in nature just as photon does. He personally thinks that nature seems to love symmetry. Now, we discover that there is a violation of symmetery in weak interaction.
 * Thljcl 17:12, 26 March 2007 (UTC)

Your assertion made on 25 March 2007 is still incorrect, Thljcl. You said, "Apparently, frequency of a body with non-zero rest mass is not directly proportional to its kinetic energy but its total energy or total relativistic mass," which simply is not true, even by your own ``derivation''. You state that the frequency of a body with non-zero rest mass is proportional to its total energy (including rest mass), but yet your last post assumes $$m_0 = 0$$ within the derivation -- so you've only shown that the frequency of a body with zero rest mass is proportional to its total energy. This is obviously true because the de Broglie relation contains the momentum term $$p$$, which from the equation

$$E=\sqrt{m_0^2c^4+p^2c^2}$$,

which you state above, clearly has no dependence on rest mass $$m_0$$, as you previously asserted. Dchristle 20:52, 1 April 2007 (UTC)

In the Article "Phase velocity" they use the total energy instead of just the kinetic one to define the "frequency of matter waves". I don't know, what is correct, but I think the wrong one should be corrected, maybe including some motivation why it should be the total or just the kinetic energy.

Historical inaccuracy; Planck hypothesis
Two changes seem in order: First, I believe that the date of the de Broglie thesis defense at the Sorbonne was 25 November 1924. (Not 1923.)

The thesis was first published in 1925 (Ann. Phys. (Paris) 3, 22 (1925)).

De Broglie got the idea for matter waves in 1923, reportedly on his birthday, 15 August (See E. McKinnon, Am. J. Phys. 44, 1047 (1976)).

He published a short note concerning the phase of matter waves later that year, in Comptes Rendus de l'Academie des Sciences (vol. 177, pp. 507-510 (1923)). De Broglie included an analysis of the Bohr hydrogen atom model, requiring the electron's phase change by an integer multiple of 2[pi] around an orbit. The de Broglie wavelength, while implicit in his analysis, was not explicitly indicated as h/p; this, however, can be derived from the the wave's phase velocity and its frequency obtained through the Planck relationship E=h[nu]. (While his 1924 thesis was passed around and discussed in the physics community, this paper was resoundingly ignored. And is currently.  It is not listed in his important publication on his Wikipedia site, for instance.)

So the first change to this article should be to change the thesis date to 1924, or to say that De Broglie got the idea of matter waves in 1923. Since it was only the 1924 work that was influential, the prefered date would be the 1924 thesis.

Second, it was Planck who proposed the Planck hypothesis in 1900 that energy and momentum are universally related through the Planck relationship E=h[nu]. It seems peculiar to call an energy-frequency relationship the "second de Broglie equation." Furthermore, if de Broglie wanted such an honor, he surely would have insisted that the energy include the relativistic rest mass, not the one presented in the article for the kinetic energy alone.

In both the 1923 Comptes Rendus paper and the 1924 thesis, de Broglie used as energy the particle's total relativistic energy to calculate the quantum frequency through the Planck relationship. The de Broglie relationship h/p gives the particle wavelength in both relativistic and non-relativistic treatments. However, the Planck frequency for a massive particle increases when the rest energy is included. De Broglie's convention of including the rest mass in the energy has several results: (1) the Planck energy-frequency relation gives a non-vanishing frequency for a massive particle at rest; (2) the phase velocity of de Broglie's "de Broglie" waves exceeds the velocity of light. McKinnon (loc. cit.) makes clear that de Broglie held onto this relativistic definition of the Planck frequency tenatiously, even after the introduction of Schroedinger's non-relativistic wave equation, where a free particle at rest has zero frequency and phase velocities are less than the speed of light.

As has been pointed out by other commentators, the derivation of the de Broglie momentum-wavelength relationship by combining the Planck energy-frequency relationship and Einstein's relativity proceeds only if the relativistic total energy, including the rest mass, is used. This was de Broglie's discovery, and the basis for his PhD.

It would be more historical to call an energy-frequency relationship a Planck relationship. Possibly the section on the "second de Broglie equation" could be renamed, or not named at all.

Or, it would seem fitting, if "de Broglie hypothesis" gets an article all by itself, wouldn't symmetry suggest a "Planck hypothesis" article? This material could be moved there. Or, since there exists a "Planck postulate" article, placed there.

128.223.23.123 00:01, 12 April 2007 (UTC)

Well, since de Broglie took total energy in the relation for matter wave frequency in his thesis, then the so-called "second de Broglie equation" should be corrected. Another reference that total energy was used is from the Quantum Mechanics part (Vol III) of Feynman Lectures On Physics, though Feynman mentioned the zero of energy can be moved arbitrarily (so as to the frequency). --Kris Huang 19:55, 19 July 2007 (UTC)

Nobel prize for PhD thesis
I believe that Johannes Diderik van der Waals, which received the Nobel prize in physics in 1910, also got it on the grounds of his PhD work. Which means that de Broglie at east wasn't the first. —Preceding unsigned comment added by 152.94.13.82 (talk) 15:43, 7 November 2007 (UTC)


 * van der Waals obtained his PhD about half a century before the prize; de Broglie's Nobel prize was awarded about half a decade after his PhD. ~ Jafet Speaker of many words 15:02, 25 August 2008 (UTC)

Editwar
I've reported the ongoing editwar at Administrators' noticeboard/3RR. Wouldn't it be a good idea to take the time and discuss the merits of the reference? Guido den Broeder (talk) 19:48, 27 June 2008 (UTC)
 * As stated above: I hold my promise though mr. W.Waggel and mrs. M.Moira vandalised -- by reverting from mr. E.Baas onwards continuously -- my very relevant Scientific reference translated. Not including the ex-link to the jlnlabs anymore. Regards: D.A. Borgdorff PEng AIEE FRIEN = 86.83.155.44 (talk) 18:47, 28 June 2008 (UTC)
 * Thanks Guido, the page is now semiprotected so you and I can edit it, but 86.83.155.44 cannot. FYI: the merits of the reference have been extensively discussed on nl:Overleg_gebruiker:86.83.155.44 and found to be lacking by all participants (except for mr Borgdorff). Vallee is a crackpot. On other wikipedias it was hardly deemed worthy of discussion and removed fortwith. Wammes Waggel (talk) 21:43, 28 June 2008 (UTC)
 * Nonetheless, all of you behaved badly here. Guido den Broeder (talk) 22:47, 28 June 2008 (UTC)

To the attention of mr. W. Waggel s.s.t.t.:
 * It's obvious that you studied nor comprehend the deep QED cq QM discrepancy that isolated on age Hon.Mr. De Broglie, together with Bohm (circa ultimo sixties) from the other quantumphysicists in their understanding of the existance of really Material Waves. Apparently with your remarks have no notion of "what matters". Though Yrs → D.A. Borgdorff = 86.83.155.44 (talk) 23:01, 28 June 2008 (UTC) See also: Bohm interpretation and in de:De-Broglie-Bohm-Theorie.
 * Moreover: never taking the reference seriously and even spells his name unconsciously wrong ... apparently without an apologetic response. Again: dAb → 86.83.155.44 (talk) 23:18, 28 June 2008 (UTC)
 * Oh, I've read it. It's baloney. You should read e.g. QED by Richard Feynman - contrary to Vallee, even the book has an article here. By the way, I do not know where you got the notion that I am "mr" - I am Wammes Waggel (M/V) to you. Respectfully yours, working under pseudonym Wammes Waggel (talk) 23:28, 28 June 2008 (UTC)
 * If you had read my pages more well, you'd understand that I already for a long time (~ 40 years) ago about those same years worked in the nuclear reactor of IRI THDelft, where Prof.dr. Van Dam promoted, and after time contacted many of the most erudited in Holland whose names I quoted there on my talkpage and else. E.G. I responded to mr. Robotje - opus citatum:
 * Geachte heer, ik zal maar duiden dat een atoom als nog geen deel-baar elementair deel-tje werd beschouwd, totdat anders bleek middels enige soorten Higgs-bosonen, ijkfotonen, gravitonen, quarks & leptonen, welke als elementairder werden beschouwd, hoewel thans de huidige inzichten " in the eyes of the beholder: back to the basics " weer algemeen gewag maken van energetische vortices, in een ruimtelijke matrix van gebroken nl:CPT-symmetrie, ondanks fijn 'besnaarde' recente ontwikkelingen. Lees anders eens van K.P. Sinha & N. Kumar over Interactions in Magnetically Ordered Solids in hun Exchange Coupling en Magnon-Phonon relaxation, dus: de interacties (mv) tussen fotonen, magnonen en fononen, - of ook het interessante werk van bijvoorbeeld Chris Quigg over Gaugefields etc., dat in renormalisation met Lie-groepstheoretische aspecten verband houdt evenals deze materiegolven de gehele interne en externe kwantumfysica bestrijken. Vriendelijk dank voor uw belangstelling heer Robotje met een beleefde groet: - D.A. Borgdorff 86.83.155.44 12 feb 2008 13:16 (CET) Denk ook eens aan bijvoorbeeld de dichotomie inzake de EPR-paradox!
 * You'll have to understand that I not only digested Richard Feynman's works, but papers of Steven Weinberg and id. Hawking, Fred Hoyle et al, apart from told very learned Dutch physicists from Casimir till 't Hooft. — Further to your gender was known of male attitude, and yourself chosen occultistics led that easy to misinformation. My name is openly ever the same. Not obscured but: D.A. Borgdorff with titles stated before. 86.83.155.44 (talk) 00:14, 29 June 2008 (UTC) → P.S.: I'll also have to draw your attention to the very recent publication from Marcoen Cabbolet M.J.T.F.: Elementary Process Theory here with ISBN 978-90-5972-232-3 -- where the book of Krityunjai Prasad Sinha, Narendra Kumar ISBN 0-19-851423-9 has been dedicated to prof.dr. M.H.L. Pryce and "Gauge Theories"... by Quigg has ISBN 0-8053-6020-4.


 * I have put back the reference to Vallée. Vallée worked closely together with De Broglie, and although his vision was not mainstream science, it certainly is noteworthy information. A first hand source for infromation on the theories of De Broglie. That this publication was not printed in big editions is not unusual: in the '70's there was no internet, many publications were typed by hand and then copied, especially information that contained other visions on items like quantum mechanics, which was more mainstream. many academic printers refused to print big editions of specialized academic information, because it did not 'sell' enough and therefor was not commercially interesting to them. That's why this source can be of quite big value for researchers nowadays (even when the theory contained in it is a bit 'dated' compared to modern scientific views and mainstream ideas), and people who look for more information into these theses of De Broglie. So a reference to this publication (which is available on the internet nowadays) is a good source for further studies. Vallée was seen as a outsider in the field just because his ideas were controversial. But did Einstein also start as a mainstream academic? DTBone (talk) 00:02, 29 June 2008 (UTC)
 * Vallée was an electrical engineer, in the 1960's working on digital electronics. In what way was he associated with de Broglie? /Pieter Kuiper (talk) 06:39, 4 July 2008 (UTC)
 * As have been proven - and also stated months ago in Holland - he was from ultimo sixties on involved with the late different point of view from De Broglie, compared with his QM colleagues in that decennium. Vallée was a QED-specialist and engineering professor in France's "nuclear" State service where his work was classified. I told you (...) so plenty of times. \ dAb / by 86.83.155.44 (talk) 12:52, 4 July 2008 (UTC)

Mr. Borgdorff, your credentials are not at issue here. Nor are they relevant. If mr Vallee is so great, may I humbly suggest you write an article about him here. Your reference would certainly be acceptable on that article. Not, however, here. It's baloney. You, who maintains to be so well versed in this subject, would have little trouble finding better references and literature than Vallee. And mr DTbone, I suspect that you are introducing a new phenomenon, cross wiki sockpuppetry (using different usernames on different wikipedias to intentionally hide that they are the same person). Interesting. I question your ability to judge the merits of said reference and have once more removed it. Feel free to once again report an editwar. Regards, Wammes Waggel (talk) 14:49, 29 June 2008 (UTC)
 * For your first remark mr. "Waggel", see into my French talkpage here and lemmata about synergy there, as well as my comments further on. -\ ir. D.A. Borgdorff MASc E.E. => unto 86.83.155.44 (talk) 09:30, 1 July 2008 (UTC)
 * @Wammes Waggel: I have some foreign language accounts, which I only use for honest and open editting. I dont use them as sockpuppets at all, because sockpuppets are supposed to be used to obscure an identity. I never lied over who I am, i.e. Tjako van Schie, pianist and composer, living in the Netherlands, Nieuwleusen, I am 47 years old, married, have 2 children, have been very active on the Dutch wiki since november 2007, where I contributed over 5200 edits in the main space area, and started many new articles. I have been fighting vandalism, reviewed new edits and new articles, and am an active and serious contributor in many serious wikiconcerning debates over there. You may know everything about me except my pincode and passwords. Here I am registered as user Dutch T-bone, on the nl wiki as gebruiker:Tjako, on the spanish and nls (Nedersaksisch) wiki as Pling, and on the others I have not yet registered, but sometimes contribute under my IP address, mainly for adding crosswiki references (interwiki links in articles), sometimes to discuss other important things with e.g. Mr. Borgdorff and/or others, mr. Borgdorff especially got my attention, because he is currently blocked for a month on the Dutch wiki for merely editing 2 characters in one of his own talk contributions, which is the most ridiculous thing where an admin abuses his buttons and doesn't even have to say 'sorry'. So put those stupid allegations of crosswiki sockpuppetry away immediately, and start serious rethinking of the allegations you've been accusing me as well as Borgdorff of. Regards, DTBone (talk) 18:01, 30 June 2008 (UTC)
 * You still don't understand, do(n't) you.? Though esteem: D.A. Borgdorff - e.i. through 86.83.155.44 (talk) 15:11, 29 June 2008 (UTC) Sr.Don Wammes W.
 * I don't understand the relevance of your reference, because you have not substantiated the relevance of your reference. Your credentials and history of employment and mention of famous physicists do not substantiate the relevance of your reference. And your mr Cabbolet failed to get his PhD because his thesis was found lacking. And indeed, I do not understand what Cabbolet has to do with Vallee, except that maybe he is also an unrecognized genius in your opinion. Cabbolet also does not make your reference any more relevant. I strongly urge you to write that article about Vallee though, you seem to be in an excellent position to do so. Regards, Wammes Waggel (talk) Esq. 15:44, 29 June 2008 (UTC)
 * If you know it better, write it yourself - that will do !. And don't keep as  MoiraMoira - going on vandalising my international edits involved, please. Wishing you succes and all the best. Always D.A. Borgdorff with → 86.83.155.44 (talk) 18:44, 29 June 2008 (UTC)

See again this recently spoken of on the Help-page: and. → With great respect and kind regards from: D.A. Borgdorff c.q. 86.83.155.44 (talk) 11:49, 30 June 2008 (UTC) abbrieviated as dAb +>

A reference about a fringe theory by mr Vallee is not relevant to the subject of this article. Wammes Waggel (talk) 05:55, 4 July 2008 (UTC)
 * Unfortunately you are going on to disrupt the importance of the Hon.: prof. R.-L. Vallée, as well as my contributions of messenger interrelated to most works of De Broglie. This is still indignified upheaval ... of which I stay aloof from. Truly Yrs: \ dAb / +> 86.83.155.44 (talk) 09:39, 4 July 2008 (UTC)
 * Because of a suddenly blocking up from action by Robotje - while defending me - I'll have to (re)place the (un)finished text hereunder in España.wiki:


 * On the contrary: ¡ Don't take that very important reference away without discussion first.! You are nó more worth than any other user ...nl:G:dAb via —86.83.155.44 (discusión) 10:08 4 jul 2008 (UTC) → Post scriptum: the lie that in France is no article about Vallée is proved by Synergie in paragraph Physique synergétique. Always, atentamente D.A. Borgdorff: —86.83.155.44 (discusión) 10:35 4 jul 2008 (UTC) → PS: I also clearly stated that the work eruditely published from De Broglie's 'own' Masson & Cie on this topic of M° René-Louis Vallée - mi traslado incluido - had been "classified" by the Public French National State Atomic CEA ultimo 1974 for obvious reasons. Saludos Cordiales y Atte: D.A. Borgdorff —86.83.155.44 (discusión) 11:14 5 jul 2008 (UTC)


 * Hoping someone been able to copy/paste insert this into the proper Spanish "equivalent" talkpage overthere ... Thanks in advance for your service. Obliged sincerely yours: D.A. Borgdorff still from 86.83.155.44 (talk) 10:56, 4 July 2008 (UTC)

Hi dAb, apparently, nobody on any version of Wikipedia ever took the trouble to explain this to you, so let me try. The general rule is that if an addition to an article is disputed, then it must be left out until such time that consensus for inclusion is reached. It does not matter whether you are right. This can indeed be very frustrating at times, since there are many ignorant people around.

Personally, I would rather have a different setup, where the opinion of knowledgeable contributors carries more weight, but unfortunately the rules are what they are, and the quality of the articles will therefore be lacking. Take into account that Wikipedia is an experiment; we will learn from it how to do better with the next generation of community-maintained encyclopediae.

Now, specifically with regard to references, unless it is a general source of information, the text should indicate why it is important to include it. That is, it should be referred to explicitly. For instance: "according to one study, ...", followed by the title between ref tags. That way, it is immediately clear to readers as well as other contributors why the reference may be relevant.

A translation of a reference can only be relevant if it helps the reader. So, a translation of a French text into Dutch would typically only be of interest on nl:Wikipedia, but not on en:Wikipedia.

If a dispute continues, i.e. users cannot come to an agreement, there are ways to get help. These ways differ between language versions, so if you don't know what to do to try and get a dispute resolved, ask any admin, or a helpdesk, or some such. Reverting is not the answer, and will only get the page protected. Guido den Broeder (talk) 12:44, 4 July 2008 (UTC)
 * Thank you mr. G. den Broeder MSc for your advice, which I responded to on my talkpage in Spain: here to take into account. With regards D.A. Borgdorff 86.83.155.44 (talk) 15:04, 4 July 2008 (UTC) → PS: on metawiki as well as some talkpages of colleagues here and else in Spain, I further explained the meaning of Vallée's references in relation with paradoxes of De Broglie, e.g. abovementioned Bohm interpretation of De Broglie-Bohm Theory. Sincerely: D.A. Borgdorff = 86.83.155.44 (talk) 18:44, 8 July 2008 (UTC)

The above Dutch mentioned translation of the book from Masson & Cie, Éditeurs: René-Louis Vallée: L'énergie électromagnétique matérielle et gravitationnelle - Paris, 1971 - is not the problem itself, but was so notified ... it was the classified edition itself (with all kinds of occult translations) that is contested of as: fringe science with yawns from a couple of biased persons with prejudice.!! This bias is awarded though, unfortunately. Kind regards: D.A. Borgdorff, e.i. = 86.83.155.44 10:53, 6 July 2008 (UTC) Further, I'm blocked up again, this time by user:Oscar 3 months for same reasons which are not scientific at all, of which I complained though. dAb = 86.83.155.44 (talk) 11:27, 11 July 2008 (UTC)

Move from 'De Broglie wave' to 'Matter wave'
I'd like to question the Jan 11 move of this article from 'De Broglie wave' to 'Matter wave'. I don't believe many physicists use the term, they use 'wavefunction', or 'De Broglie wave' when referring to historical quantum mechanics. 'Matter wave' is a descriptive term used in elementary explanations of quantum mechanics. I don't necessarily oppose the move, but I'd like to hear what others think. -- Chetvorno TALK 12:00, 13 March 2009 (UTC)
 * Matter waves seem to show up quite a bit in papers about condensed matter physics. I'm not clear if that is the same topic as de Broglie waves.&mdash;RJH (talk) 20:35, 4 August 2009 (UTC)

Spatial Zeno effect
If an object (particle) is observed with frequency $$\Omega\gg\omega$$ in a half-space (say, $$y<0$$), then this observation prevents the particle, which stays in the half-space $$y>0$$ from entry into this half-space $$y<0$$.

Huh? I presume this means "If an object (particle) is observed with frequency $$\Omega\gg\omega$$ in a half-space (say, $$y<0$$), then this observation prevents the particle, which stays in the other half-space ($$y>0$$), from entering this half-space ($$y<0$$)."

However, I haven't studied this stuff, so someone should check it. While you're there, you can bypass a redirect (Zeno effect -> Quantum Zeno effect). Brian Jason Drake 08:55, 18 April 2009 (UTC)


 * I don't claim to be a expert but I'm sick of the ambiguous term "Observe" when used on systems of this scale. One might say Sessile Fielder observes the baseball with his bat. In essence this is the saying the same thing. Now we can put away our faerie crystals and get back to science. — Preceding unsigned comment added by 198.2.4.2 (talk) 16:40, 10 December 2011 (UTC)

The de Broglie relations
I removed the following sentences as they are redundant, unclear and (as far as I can see) insignificant.


 * The greater the energy, the larger the frequency and the shorter (smaller) the wavelength. Given the relationship between wavelength and frequency, it follows that short wavelengths are more energetic than long wavelengths.

Brian Jason Drake 08:04, 22 April 2009 (UTC)

pronunciation
The French pronunciation is linked at Louis de Broglie. It's irrelevant here, where we need the English pronunciation. We can have it in addition to the English, though I fail to see the point, since no-one uses the French pronunciation when talking QM in English. kwami (talk) 17:31, 5 May 2009 (UTC)

Multiple particles
This article should discuss the quantum mechanical derivation of the de Broglie wavelength for a system of several particles. (The proof is not too complicated, but I cannot remember it now. It is a common question if there is a physical sense of speaking of the atom/molecule/ball wavelength. It is, but it should be demonstrated clearly why.) --FDominec (talk) 23:12, 26 February 2011 (UTC)

Frequency
If E is the kinetic energy of the particle, $$E=mv^2/2=\gamma m_0v^2/2$$. That's not wat the article says Nijdam (talk) 17:13, 2 July 2011 (UTC)


 * The relativistic equation for total energy is $$E=\gamma m_0c^2$$. The kinetic energy is given by the total energy minus the rest energy: $$E_{kin}=\gamma m_0c^2 -m_0c^2 = (\gamma-1)m_0c^2$$.Ragnarstroberg (talk) 23:38, 12 September 2011 (UTC)

Function?
in the history section it says that the wave length is a function of Planck's constant. This seems a strange way of expressing to me, what is the meaning of a function of a constant? Nijdam (talk) 20:28, 6 August 2011 (UTC)


 * I changed this to "equal to". I think this makes more sense.Ragnarstroberg (talk) 23:40, 12 September 2011 (UTC)

Historical Context
I think the Historical Context section should be overhauled. Einstein's equations relating wavelength and momentum for a photon should be given for context, and the connection with Niels Bohr and the Rydberg equation should be either be made more explicit or dropped. Also, the discussion of the wavelength at different scales belongs in a different section - it's not historical. If there are no objections, I'll make the changes when I get a chance.Ragnarstroberg (talk) 03:44, 13 September 2011 (UTC)

Compton Scattering
I changed the line

"Just as Arthur Compton demonstrated the particle nature of light"

to

"Just as the photoelectric effect demonstrated the particle nature of light"

because Compton scattering wasn't observed until 1923 whereas the photoelectic effect goes back to Lenard's work in the 19th Century, — Preceding unsigned comment added by WeOwnTheNight (talk • contribs) 18:27, 2 October 2011 (UTC)

Unproven Research
I removed the following text from the beginning of the article because it is unproven research and has only just begun the process of peer review. It therefore does not belong in an encyclopedia. If this research survives peer review and becomes widely accepted, it can be put in. As such, the text does nothing for the article, other than to confuse.

"However, a recent (2011) pre-print of a research article (appeared at http://arxiv.org/abs/1110.4263), by the researchers (Himanshu Chauhan. et. al.) from the well known Indian engineering institution (Delhi Technological University, formerly Delhi College of Engineering), reported de Broglie's frequency expression for matter waves, as flawed. The super-luminal phase velocity expression for matter waves was also reported to be inadequate, in this paper."

reply for the writer of THE ABOVE "Unproven Research"
I would like to inform the above person (who deleted the text) that the work which is being presented in the paper is NOT UNPROVEN. For once, if you would try to have a look of the research article, than only you can understand the inadequacies of de Broglie's theory and their rectifications. But before that, you cannot say that IT IS UNPROVEN!!!!!. De broglie's theory is one of the pillars of quantum mechanics (other being the uncertainty principle) and thus it's flawlessness is a vital issue. If some work is still under the peer-review phase, that does not invalidates the concepts that are being proposed in the paper. Also, it does not implies that the work is of inferior quality, so that someone can delete the text related to it.

In the paper, NUMEROUS VERIFICATIONS AND PROOFS for the proposed concepts and expressions are provided, which are enough to satisfy someone in favor of the work!!!!! The text was written with the intention of informing a wide group of physicists, and specially for those who are working in the field of matter waves and their applications.

And pls let me know how can it CONFUSE someone????? Just because of the reason, that it is against some well established concept????? Then Dear friend, I would like to say that every revolutionary concept do seems like a day-dream or speculation at first look..... But this puts forth a question for the physics community that "WHERE DO WE LIE????". If new concepts are not welcomed, than whats the point of saying that "physics is EVOLVING!!!!"???????

I would apologize if my words are rigid....... But, it is because of the reason that some new theory or concept, which is against of some well established work, gets defamed in front of scientific community...... Which is NOT GOOD AT ALL.........

THANK YOU......


 * It's not published and a primary source; thus it has no due weight. Wikipedia reports on the mainstream position as given in reliable secondary sources, thus if this new formulation becomes mainstream with mentions in reliable secondary sources it would then require a mention in the article. IRWolfie- (talk) 22:28, 31 December 2011 (UTC)

Stop re-inserting the text and attempt to discuss it on the talk page. I suggest you also check WP:OR and WP:UNDUE. IRWolfie- (talk) 13:30, 1 January 2012 (UTC)

I could have re-inserted it now again..... But we will definitely talk after some days..........

Just Wait 4 it........ — Preceding unsigned comment added by 116.202.94.98 (talk) 17:29, 1 January 2012 (UTC)


 * What are you referring to? IRWolfie- (talk) 21:04, 1 January 2012 (UTC)

U will get 2 know about it..... soon,....... — Preceding unsigned comment added by 180.215.201.64 (talk) 14:44, 2 January 2012 (UTC)

image of the propagation of a plane wave
For a plane wave the amplitude in each x, at each time t, should be equal to |A|^2 and not oscillate, as the image suggests using the opacity. — Preceding unsigned comment added by 78.22.169.35 (talk) 09:53, 9 January 2013 (UTC)

merging from
How about creating a new section "group and phase velocity" merging from Group_velocity and Phase_velocity? Fgnievinski (talk) 14:52, 27 September 2013 (UTC)

Matter wave clocks
There is a new stub article on matter wave clocks, but I am wondering whether part of it really belongs here. Hoping you can contribute to the discussion at Talk:Matter wave clock &mdash; Cheers, Steelpillow (Talk) 08:40, 30 June 2014 (UTC)

"Babbling" edit
At this place one sees that Cohen-Tannoudji et al. write

$$\mathbf p = \hbar \mathbf k$$

as one of the Planck-Einstein relations. When I copied that into the article I should have given the reference, but I carelessly assumed it was too well known to need one.

The undoing of my copying that into the article is justified by an edit summary that says my edit is "mathematically nonsensical...whether conceptually or typographically". It seems that the editor who undid my edit thinks Cohen-Tannoudji et al. are writing mathematical nonsense. Perhaps he will explain why he thinks so?Chjoaygame (talk) 01:38, 21 July 2014 (UTC)


 * Your edit to the equations left this in place:

The equation can be equivalently written as

using the definitions
 * $$\hbar=h/2\pi $$ is the reduced Planck's constant (also known as Dirac's constant, pronounced "h-bar"),
 * $$\mathbf k= 2\pi \mathbf p$$ is the angular wavevector,
 * $$\omega=2\pi f$$ is the angular frequency.


 * In this, P resolves to (h / 2&pi;) x 2&pi;P = hP which is clearly nonsense.
 * You also say that the (first) pair of scalar equations are equivalent to the (second) pair of vector equations. Whatever equivalence you have in mind is not a mathematical one. Your rationale for chaning the original form is entirely unclear and, since your execution of that change was garbled, it was not possible to disentangle your intent from any typographical errors you may have introduced. BTW, the "babble" comment, aka technobabble as per the previous discussion, was for a different edit on a different issue that you do not refer to here. Best not to mix the two issues vs. edit comments. &mdash; Cheers, Steelpillow (Talk) 09:50, 21 July 2014 (UTC)


 * Yes, you are right that my edit's


 * $$\mathbf k= 2\pi \mathbf p$$ is the angular wavevector,


 * was wrong. It should have read


 * $$\mathbf k=2\pi\mathbf p /(p\lambda)$$ is the angular wavevector.


 * I am sorry for this mistake.


 * The article's scalar formulas


 * and my edit's correct vector formulas


 * are perhaps not equivalent, but they are closely related.Chjoaygame (talk) 12:34, 21 July 2014 (UTC)


 * That makes a lot more sense. Perhaps your corrected version could go after the first two (scalar) variants, rather than replacing the second? Also, I don't know if there might customarily be a more elegant expression for k? Five variables seems a bit OTT. &mdash; Cheers, Steelpillow (Talk) 13:45, 21 July 2014 (UTC)


 * Yes, the expression $$\mathbf k=2\pi\mathbf p /(p\lambda)$$ is a bit clumsy. The term $$p$$ is of course just an abbreviation for $$|\mathbf p|$$. One might instead write $$\mathbf k=2\pi\mathbf{\hat p} /\lambda$$.Chjoaygame (talk) 14:08, 21 July 2014 (UTC)


 * I've tried to simplify it by just stating the vectorised equation, and providing links to the articles which explain what all the quantities are. I don't think we need to work through the calculation to transform one to the other here, that would be necessary in a textbook but it's diversion from the focus of the article here.  Djr32 (talk) 18:47, 21 July 2014 (UTC)


 * To me that now appears inconsistent with the treatment given lower down in the section on four-vectors, which states that the two vector equations are equivalent to just one of them. I also remain concerned at saying that a scalar equation "can also be written as" a vector equation. To me, these are different equations about different entities - the one a subset of the other, but not its equivalent. Or, am I being naive? &mdash; Cheers, Steelpillow (Talk) 19:12, 21 July 2014 (UTC)


 * I don't agree with your first point - the equations in the second box can be written as the one equation later using four vectors, but I think that's what it says. I agree that the first box is a subset of the first, would "or in vector form" be better than "can also be written as"?  Djr32 (talk) 21:54, 21 July 2014 (UTC)


 * Of course, you are right about the four-vector form. For the other, I think it might be clearer to be a little more explicit, say "Taking the direction of movement into account, the equivalent vector equations may be written as:" (i.e, the "equivalence" is explained as an equivalent physical situation and not as a strict mathematical equivalence)? &mdash; Cheers, Steelpillow (Talk) 11:04, 22 July 2014 (UTC)

Reduced Planck constant
Reduced Planck constant is equal to the Planck constant divided by 2π: ħ = h/(2π). It isn't equal to the Planck constant divided by 2 then multiplied by π: ħ = h/2π (in this article). Minh Tấn (talk) 05:01, 5 January 2018 (UTC)

The kinetic energy or the total energy?
Under the de Broglie relations it says specifically that they relate frequency to the kinetic energy only, not to the total energy, but under the special relativity section it calculates the frequency such that it would give the total energy. Is there an error or am I missing something?--88.196.181.17 (talk) 10:27, 18 April 2013 (UTC)


 * In the years since this comment the page has been repaired. I don't see the kinetic energy being used for frequency now. Thanks! Johnjbarton (talk) 19:30, 9 May 2023 (UTC)

Reason for hatnote
The article contains a hatnote "The de Broglie relations redirect here.": why is this relevant, what would be lost by omitting it? It offers no alternative definitions for "The de Broglie relations", and thus seems superfluous. crh23 (talk) 16:10, 27 March 2015 (UTC)

Pronunciation of "de Broglie"
Suggest removing the pronunciation of "de Broglie" from this page as it is at de Broglie already, where more detail is given on the pronunciation. &mdash; 91.238.123.116 (talk) 10:34, 26 July 2016 (UTC)

Physical meaning
This section has just been added by an editor who has formerly appeared to support the particle interpretation of wave-particle duality and related quantum phenomena. I personally find the current section to be twisted and unsupportable technobabble, aimed primarily at repeating the word "particle" as often as possible. For example the quantization of an interaction is not the "meaning" of the wave description, it is a consequence of it. "Duane's principle" is not explained, the linked article on Duane makes no mention of it and Googling it reveals just 64 hits, mostly in the context of philosophical and pseudo-science topics. IMHO this section should be summarily deleted, but having crossed swords with this editor before I am reluctant to do so myself. &mdash; Cheers, Steelpillow (Talk) 13:27, 20 July 2014 (UTC)


 * I entirely agree. To expand slightly, in my view, there shouldn't be a section called "physical meaning" as it implies that the de Broglie hypothesis is some sort of metaphor, and that there might be sections of the article which aren't about its physical meaning.  I have deleted the problematic section. Djr32 (talk) 18:23, 20 July 2014 (UTC)


 * I will not expand on the point that the above "I entirely agree" supports ad hominem rhetoric. I will just focus on the rest of the just above comment by Djr32. The objection seems to be entirely against the heading of the now deleted section that is just above called "problematic". No criticism of the content of the section is offered. It seems to me that it would be reasonable for me to restore the section with some other heading, such as perhaps Quantal momentum transfer?Chjoaygame (talk)


 * Djr32 agreed with me, there was no need to repeat the points I made simply in order to support them. Your edit was inappropriate to this article and will remain so regardless of the section title. &mdash; Cheers, Steelpillow (Talk) 10:10, 21 July 2014 (UTC)


 * Yes, I agree with sentences 2, 3 and 4 of Steelpillow's post, and his proposed solution in the final sentence. I wasn't following who thought what in the matter wave clock discussion, so I have no view on whether his first sentence is correct or not, so apologies for that.  I think both the section heading and the content should be deleted.  Djr32 (talk) 18:51, 21 July 2014 (UTC)

Interpretations
Rethinking the above outcome a little, would a section on Interpretations be useful? It would allow brief pointers to the controversy surrounding the issue, and perhaps allow editors such as Chjoaygame a little more latitude in summarising and linking to their own favoured interpretation? The section on matter wave clocks might end up in there too, I'm not sure. &mdash; Cheers, Steelpillow (Talk) I believe the section on interpretation is appropriate but agree that it was poorly written, redundant in places and incoherent. I’ve been working on making sense of it.Voyajer (talk) 13:03, 29 October 2021 (UTC)


 * The disputed section (at least now) reads as history. I retitle the section "Impact on the early history of quantum mechanics" to match what I read.
 * The final paragraph is not quite history and it is hard to follow. I may follow up on that. Johnjbarton (talk) 18:28, 5 May 2023 (UTC)

Impact on the early history of quantum mechanics
I reworked the disputed section again. The topic in this section is the impact of de Broglie's matter wave idea on the early development of QM. I did not verify the history but it seems plausible as is.

I removed one sentence and one paragraph.

The sentence had a bad citation -- the text concerned elastic properties of solids -- and mentioned an old hypothesis on particle diffraction. That idea -- Duane's hypothesis -- was speculative back in 1926 and had no impact since.

The paragraph discussed mathematically ideas -- real vs configuration vs Hilbert vs phase spaces -- in "ordinary language" but it does not work as encyclopedia material on matter waves. The topic is too complex for a paragraph and anyway it's not clear how it connects to the main topic on this page.

Overall I have the impression that this material was intended to suggest that matter waves are not settled science. While there remain controversies, all recent work reinforces the basic notions. Moreover this page might be a good place for a link to other views, its not the right venue to discuss them IMO. Johnjbarton (talk) 00:20, 6 May 2023 (UTC)

An "object that transfers its momentum quantally"?
I have absolutely no idea what "the De Broglie hypothesis is expected to apply to any object that transfers its momentum quantally" means. What does it mean for an object to transfer its momentum quantally? (Are there some objects that don't? Do these objects have wave-like properties?) The standard description of the de Broglie hypothesis is that all matter has wave-like properties. The reference is to a 1937 book by Alfred Landé. The Landé interpretation is listed on our page of Minority interpretations of quantum mechanics, does this statement need to be presented more in context of more mainstream interpretations? Djr32 (talk) 22:04, 26 July 2014 (UTC)


 * Thank you for this reasoned comment.


 * My edit changed the sentence "In general, the De Broglie hypothesis is expected to apply to any well isolated object" into the sentence "In general, the De Broglie hypothesis is expected to apply to any object that transfers its momentum quantally."


 * Editor Djr32 asks "What does it mean for an object to transfer its momentum quantally?" He adds that "The standard description of the de Broglie hypothesis is that all matter has wave-like properties."


 * The article's sentence that my edit replaced seems to have more detail in mind than just "all matter"; it restricts its focus to "any well isolated object". Why that restriction, perhaps Editor Djr32 would like to tell us? Perhaps he would like simply to remove that restrictive sentence that stood before my edit?


 * As for that former sentence, I would say (as did my edit summary) that it is unsourced and looks as if it was made up off the top of an editor's head for lack of something more precisely meaningful.


 * Einstein made the big step to establishing the physical reality of the photon by arguing that it transferred its momentum quantally. Perhaps Editor Djr32 would prefer some wording other than 'transfer its momentum quantally'? But does he dispute Einstein's basic idea there? I don't think so.


 * The matter waves are always detected by interactions of the particles with other objects, in diffraction experiments, not on "well isolated objects". In a diffraction experiment, the momentum of the particle changes by momentum transfer, either from a spatially periodic structure such as a crystal, or from a temporally periodic structure such as a photon. The amount transferred is quantal in the crystal or photon, and consequently in the particle. In both cases, there can be various numbers of several quanta of momentum transferred. That is why there are several fringes in the diffraction pattern; that is why it is a diffraction pattern. The de Broglie wave has its wavelength determined by the formula $λ = h / p$, where $p$ denotes a momentum. That says that momentum is central to the de Broglie wave concept.


 * I think the just foregoing paragraph is enough to justify in reason the edit that I made. I claim that Landé's text is a Wikipedia-defined reliable source for it.


 * If Editor Djr32 has a reasoned argument of his own why Landé's physics is wrong on this point, I would be very keen to learn of it. If Editor Djr32 has some reliable source that says Landé is wrong about this, I would be very keen to learn of it, and perhaps he will tell us of it? Then one could perhaps say that Landé's physics was controversial? I don't at present have access to the second edition (1951) of Landé's 1937 textbook that I cited, and it may take me some time to get it. But from other books by Landé I feel reasonably confident that he didn't change his mind about this. (Changes of mind here are relevant, because de Broglie says that he changed his mind about the nature of the matter wave, after some decades of thinking about it, a point absent from the present article.)


 * In short, my edit tried to replace a loose editorial opinion with a reliably sourced piece of physics. I think that physics is right. Very likely my wording can be improved.Chjoaygame (talk) 02:23, 27 July 2014 (UTC)Chjoaygame (talk) 02:28, 27 July 2014 (UTC)


 * "Perhaps Editor Djr32 would prefer some wording other than 'transfer its momentum quantally'?" - I would say, this is a trivial statement, it need not be made.
 * I don't know if it is Lande's interpretation, but Chjoaygame is certainly applying a strong pro-particle interpretation in claiming that the momentum is changed during a diffraction event. Consider for example the circular "target" pattern of ripples formed by passing a series of electrons through a small hole. The standard model ascribes no certain momentum to any electron until it has made its localised spot on the detector. The claim that momentum is first towards the hole and then veers off to one of the ripples is based on the classical model and has known flaws of a very serious nature, such as the application of Newton's laws to the bending effect. We all know very well that Lande's model is a minority one, as Djr32 has already pointed out. That battle is not to be refought here. In short, Chjoaygame is pushing their own PoV. I have pulled them up about this before but the message is not yet sticking - they are still at the stage of hopeful wriggling around and cherry-picking of words from policy rather than sticking to the spirit. If anybody would like links to the relevant policies, let me know and I can provide them. &mdash; Cheers, Steelpillow (Talk) 10:26, 27 July 2014 (UTC)


 * I don't have ready access to any QM books right now, but the idea that all matter has wave-like properties shouldn't be difficult to source. For example, in Wave–particle duality it's attributed to Brian Greene in The Elegant Universe, quoting "all matter has a wave-like character" (page 104). (As I don't have the book myself, I can't check the context, so I won't add it to the article at present.)


 * Chjoaygame: Your comment about a particle being diffracted by a crystal shows the problem with your sentence - quantisation is a property of the interaction, not either of the things interacting. The diffraction pattern seen when a particle is scattered by a crystal is set by the particle's wavelength (i.e. momentum) and the periodicity of the crystal. The momentum of a free particle is not quantised - if you applied an identical particle beam to a different crystal, you would see completely different diffraction pattern - and it would clearly be silly to say that the de Broglie hypothesis applies to the (macroscopic) crystal but not to the particle.


 * I don't particularly want to get involved in the question of "well-isolated", I didn't write that sentence, and it's a separate discussion. For completeness, the question of "how big an object can show wave-like behaviour?" (or alternatively "why don't we perceive quantum effects in everyday life?") has had a lot of attention - see, for example,  Wave–particle duality - and I don't know how complicated a treatment of it is appropriate here.  Djr32 (talk) 13:05, 27 July 2014 (UTC)


 * Thank you for this helpful advice.Chjoaygame (talk) 17:23, 27 July 2014 (UTC)

Quantal momentum transfer in the old quantum theory
This topic is back in new guise. Half the discussion is about light quanta, which are not matter waves at all, the rest is shrouded in unexplained academic allusions. I am utterly lost as to the point being made. If it is that momentum is being transferred during diffraction events, then: a) the relevant points from Epstein and Ehrenfest need to be explicitly set out, and b) the relevance to matter waves needs explaining. Do any of the cited sources even mention "momentum transfer" or similar? &mdash; Cheers, Steelpillow (Talk) 13:03, 14 September 2014 (UTC)


 * The kind of information you are asking for is supplied in the references. At present I am not sure that this section of the article should show such detail.
 * You write "Half the discussion is about light quanta, which are not matter waves at all,..." The subsection in question was initially posted immediately after "This division was challenged when, in his 1905 paper on the photoelectric effect, Albert Einstein postulated that light was emitted and absorbed as localized packets, or "quanta" (light quanta are now called photons). These quanta would have an energy $$E=h\nu$$ where $$\scriptstyle \nu$$ is the frequency of the light and h is Planck’s constant. In the modern convention, frequency is symbolized by f as is done in the rest of this article" in the historical context section. You have taken it out of that context, and now you want to know why it is relevant. Some diffraction clocks work by transfer of photon momentum to matter. Such transfer is discussed by Duane in his article, which is the key to this section. The physics here is that de Broglie waves are experimentally detected by diffraction, which is fundamentally the same for waves and particles. That is the old quantum theory explanation for matter waves, a connection recognized by Born in July 1925, before the invention of quantum mechanics.Chjoaygame (talk) 16:29, 14 September 2014 (UTC)
 * Thank you for the link on momentum transfer. Dating from 1923, it certainly qualifies as "old". But once again it deals with massless photons. Your sources for the article do need to be relevant to massive particles. I have to say that I have never heard of a "diffraction clock" and nor, it seems, has Google. Perhaps you mean matter wave clocks or some other form of atomic clock? Whatever, the reason why momentum transfer is a significant issue also needs to be explained - and reliably sourced. &mdash; Cheers, Steelpillow (Talk) 18:26, 14 September 2014 (UTC)


 * It's back... and just as problematic as last time! I would go further than your comment: as far as I can see, the whole section is about the diffraction of X-ray photons by crystals, which isn't a "matter behaving as waves" thing at all. That also applies to Epstein and Ehrenfest's conclusion that the diffraction of light can be explained by a quantum theory - it's true, but it doesn't belong in this article. I suggest that the added section should be deleted. Djr32 (talk) 19:19, 14 September 2014 (UTC)


 * In the current version, it says "only a few physicists express this idea for light wave diffraction", the idea that diffraction by periodic objects (crystals, diffraction gratings, etc.) changes momentum (wavevector) by a reciprocal lattice vector. I disagree! In my informal small survey, ~100% of textbooks in visible-light or x-ray optics describe this fact, and ~100% of optical physicists are aware of it. I was randomly chatting about it as recently as yesterday. Indeed, it is a basic, well-known fact that when something satisfying a wave equation interacts with something with a periodic structure, the k-vector changes will be quantized. (Proof: Write the wave equation in fourier space...)


 * Therefore, saying "XYZ has quantized momentum transfer from periodic structures" is really just an overly-complex way to say "XYZ exhibits diffraction". The fact that these two statements are the same is an interesting mathematical fact, and we can thank pioneers like William Duane for proving this fact, but this fact is off-topic in this article. It's related to the theory of waves in general, rather than the specific physics question of whether matter is a wave. In summary, I don't see how this paragraph makes any sense and I think it should be deleted. --Steve (talk) 15:07, 24 September 2014 (UTC)


 * Thank you for this careful comment.


 * I put in those words, about photons, which at your suggestion I have now removed, because they were in the cited text, and because they continued the view taken by the previous editor of that sentence.


 * It is common to propose that diffraction is specifically a wave phenomenon. Niels Bohr, for example, placed much emphasis on this. It is directly in conflict with the viewpoint that your comment expresses, and with which I agree, "that diffraction by periodic objects (crystals, diffraction gratings, etc.) changes momentum (wavevector) by a reciprocal lattice vector" is well known to physicists and that we can thank Duane for pointing this out. In other words, physically thinking, diffraction is not specifically a wave phenomenon; this is clear from Heisenberg's 1930 comments on it that are cited here. Therefore article's message, that matter has some wavelike characteristics, needs some interpretive comment in the article, as is suggested by the unreferenced paragraph that just precedes the one that you are proposing to delete. I have added some words to clarify why this is relevant.Chjoaygame (talk) 16:19, 24 September 2014 (UTC)


 * This article is about matter waves. If you interpret momentum to signify a particle, then you are going off-topic. The only bit that is relevant to the present article is, what then is the wave function interpreted as? &mdash; Cheers, Steelpillow (Talk) 17:13, 24 September 2014 (UTC)


 * "Matter waves" are observed in diffraction observed by detection of patterns formed by many particles that have arrived one by one at the detecting screen. Chjoaygame, about 18:20, 24 September 2014.
 * I thought that the only things observed were the diffraction patterns themselves. In what sense are matter waves observed? &mdash; Cheers, Steelpillow (Talk) 18:43, 24 September 2014 (UTC)


 * Are you proposing that "matter waves" are not observable, or that they are not observed? If you want to say that, perhaps it should be said explicitly in the article? I am not sure of the place of the unobservable in quantum physics. At least for Heisenberg, the theory should consist entirely of observable entities. So far as I know, that view prevails. Accepting that, if one wants to say that "matter waves" are observed, I think one has to say that it is in or through diffraction patterns.


 * Talk of matter waves suggests that there are waves that are not matter waves. Light waves suggest themselves as candidates. Matter waves are observed in processes in which inputs suffer adventures and lead to outputs. The inputs come from preparatory devices which supply matter, which is distinguished from light by its detection as particles that are not photons. So also for the outputs. During the intermediate adventures, we do not try to think in the same terms as we do when we identify the inputs and outputs respectively. We use the wave functions or the kets as vehicles that carry the process through, while temporarily avoiding those input and output terms. But the diffraction patterns for matter waves are patterns of outputs, detected matter particles that arrive one by one at the detection screen. Consequently, in physics, talk of matter waves presupposes and necessarily involves material particles. Chjoaygame, about 19:30, 24 September 2014.
 * So, I take it you mean that "matter waves are observed ... in and through diffraction patterns", i.e. they are indirectly inferred from the pattern. But then you say that the wave presupposes the particle. That is definitively a minority interpretation, but it is not necessary to invoke diffraction in order to make that statement - just to reference it. &mdash; Cheers, Steelpillow (Talk) 20:17, 24 September 2014 (UTC)

In the present lead, one reads

"The De Broglie relations show that the wavelength is inversely proportional to the momentum of a particle and it is therefore called the de Broglie wavelength. Also the frequency of the matter waves, as deduced by de Broglie, is directly proportional to the total energy E (sum of its rest energy and the kinetic energy) of a particle."

For this, the article's current reference is Resnick and Eisberg, second edition, 1985.

On this basis, by the criterion of your just above comment, the article is currently written in terms of a definitively minority interpretation. Are you saying that Resnick and Eisberg are putting a definitively minority interpretation? Perhaps something should be done about that? For that, it may be difficult to know where to turn. In the 1928 Nature version of the Como lecture, Bohr writes "The individuality of the elementary electrical corpuscles is forced on us by general evidence. ..." Is Bohr here expressing a definitively minority interpretation? Born in 1953 writes "... the steady state of an incoming wave (representing a beam of 'messenger' particles)..." and "I think that in spite of these abnormities (sic) the concept of particle cannot be discarded." In that paper he also writes "I think that neither of these extremist views can be maintained." I think your above comment seems to be trying to expunge the particle presupposition in a way that I think Born regards as extremist and rejects. Is Born expressing a definitively minority interpretation?

Fortunately, I am not proposing to put into the article the words "the wave presupposes the particle". So I do not need to actually put into the article the just foregoing references for them. The current version of the article does the job.

Your above comment seems to dismiss without reason my point that for observation of matter waves, one must invoke diffraction, and that for matter waves to be regarded as quantum physical, they should be observable. Chjoaygame, about 23:45, 24 September 2014.

Though likely superfluous, here are some references for the matter wave presupposing the particle. (1) Medicus, H.A. (1974), Fifty years of matter waves, Physics Today 27: 38-45: "When did de Broglie arrive at the revolutionary idea of attributing wave properties to particles?" (2) Max Jammer (1966), on page 243, referring to de Broglie (1924), writes "De Broglie considered the motion of a particle" and further on he quotes de Broglie: "any moving body may be accompanied by a wave." (3) Mehra & Rechenberg (2001) volume 6, part 2, p. 706: "the concept of matter waves, which described atomic particles by a wave packet". Chjoaygame, about 03:15, 25 September 2014.

As it happens, the word 'particle' does not appear in the text of the paragraph under discussion. So references for it are not needed.Chjoaygame (talk) 05:09, 25 September 2014 (UTC)


 * There is a huge difference between acknowledging wave-particle duality and assuming that the particle is the more fundamental. The fact that a diffraction pattern is evidence of a wave effect is of course part of the mainstream and is discussed in the section on Experimental confirmation, there is no need for you to argue that point. But it does not in itself provide any interpretation, it does not explain the underlying nature of that wave effect. Nor is diffraction the only such wave effect. If matter is just particles as you seem to think, what exactly are all these damn waves doing here in the math? This is the aspect that you need to address. &mdash; Cheers, Steelpillow (Talk) 10:51, 25 September 2014 (UTC)


 * I do not see it as useful that I should try to reply to this.Chjoaygame (talk) 12:56, 25 September 2014 (UTC)

meaning of frequency
It is a bit dangerous to speak of the frequency of a matter wave. The relation $$E=h\nu+E_0$$ depends on the arbitrary fixing of the zero-level energy $$E_0$$ which is unobservable, thus the frequency itself is unobservable (and unfixed). Only the wavelength $$\lambda$$ is physically relevant, since it does not depend on the choice of $$E_0$$; the reason being that the "diffraction index" $$n$$depends on $$E_0$$ in such a way that $$\lambda=1/(n\nu)$$ is constant. This fact is explicitly mentioned in Schrodinger's 1926 paper. 