Wikipedia talk:WikiProject Physics/Archive June 2013

Mass not from Higgs?

I saw a new video on YouTube which claims that most of mass is not from the Higgs mechanism after all. Please see YouTube video "Your Mass is NOT from Higgs Boson" by 1veritasium. Rather he says that it is from the energy needed to suppress background fluctuations of the chromodynamic field in the 'flux tubes' connecting the quarks within nucleons. Is this right? JRSpriggs (talk) 06:33, 9 May 2013 (UTC)

Isn't the Lund string model and QCD string for quark confinement separate from the Higgs mechanism? (That's as I know so far... could be wrong). M∧Ŝc²ħεИ_τlk 06:38, 9 May 2013 (UTC)

He also says that our diagram File:Quark structure proton.svg is wrong, i.e. that within a proton there is one Y-shaped flux tube, not three straight-line flux tubes. JRSpriggs (talk) 06:49, 9 May 2013 (UTC)

The Dual Ginzburg-Landau theory is an approximation of QCD and does give a prediction Y-shaped flux tubes; see for instance, [1]. But I don't know if such a prediction has been verified either in lattice QCD or in experimental particle physics. --Mark viking (talk) 12:11, 9 May 2013 (UTC)

Mark and Maschen, thanks for your responses. You seem to be implying that 1veritasium's video is consistent with the best available theoretical thinking. Right? JRSpriggs (talk) 14:51, 9 May 2013 (UTC)

I watched the video and most of what he was gesticulating about seemed reasonably consistent with current thought. Digging deeper, this paper confirms that there is some evidence that Y junction flux tubes have been seen in lattice QCD calculations and that most of the mass of baryons like protons and neutrons is bound up in the confinement potential energy, whether you take an asymptotic $1/N_{c}$ approach or a flux tube approach. --Mark viking (talk) 05:06, 10 May 2013 (UTC)

Still, this doesn't explain the missing mass of the universe (dark matter), which is not affected by anything but gravity, so is therefore not interactive with the higgs field? -- 65.94.76.126 (talk) 04:48, 10 May 2013 (UTC)

To 65.94.76.126: Dark matter is characterized by having little or no interaction with electromagnetism and being non-baryonic (i.e. not composed of quarks) and $\rho +{\frac {3p}{c^{2}}}>0\,$ (so that it causes the expansion of the universe to slow). This says nothing about whether it interacts with the Higgs boson. JRSpriggs (talk) 10:03, 10 May 2013 (UTC)

I did not watch the video, but the claim that most of our mass is not due to the Higgs mechanism is well known and is represented correctly by our (wikipedia) pages. The Higg's mechanism is responsible only for the mass of elementary particles such as electrons and quarks, etc. (See the lead of Higgs mechanism.) But most of our mass is due to neutrons and protons which are composite particles. Their masses are significantly greater than the elementary quarks that make them up. (See proton#Quarks and the mass of the proton.) This mass difference is due to the energy of gluon, if I understand it correctly, which is unrelated to the Higgs mechanism. Mark and Maschen know much more about it than I. I would have no hope, of understanding anything from their level. It took me a while to understand what they were saying, though, which is why I wrote this remark.TStein (talk) 20:16, 13 May 2013 (UTC)

The video and the article linked don't make clear a fairly prosaic explanation of much of the mass: kinetic energy of the quarks. This is an angle emphasized heavily by Frank Wilczek in his book The Lightness of Being. Their confinement ensures that in the ground state, they have sufficient momentum to be travelling very close to the speed of light. It is a while back that I read it, but I got the impression that this relativistic mass was the dominant source of mass (perhaps 95% of the mass of the proton, if I'm not misremembering it), greater by far than any contribution from gluon fields and all other mechanisms. The elaboration on the exact nature of the gluon tubes seems to me to be missing the point. — Quondum 20:24, 4 June 2013 (UTC)

To Quondum: Since kinetic energy (and its equivalent mass) is proportional to rest mass (due to Higgs), this does not take Higgs out of the picture. The kinetic energy of particles without rest mass (like photons) could be anything (invariant under a change of scale), so it is inconsistent with the fact that bulk matter has a definite mass. JRSpriggs (talk) 21:34, 4 June 2013 (UTC)

To JRSprings: Actually there is one problem. If classically there is a scale symmetry on the quantum level it can be broken (see dimensional transmutation and conformal anomaly) There is a scale anomaly in QCD with massless fermions, the mass scale $\Lambda _{QCD}$ is introduced in radiative corrections. Though the trace of scale invariance is still there - this new mass scale is arbitrary, but every other mass is proportional to it (and in reality only the proportions of the observable are relevant). That's funny, I just mentioned at the end of discussion another example... Of course in reality fermions and vector bosons have a mass thanks to a Higgs and this new scale is fixed by these masses. Yes, they are not responsible for much mass in the universe. No, they are not accounted by QCD confinement of massless particles (electrons don't even interact strongly) VeNoo (talk) 22:01, 4 June 2013 (UTC)

To JRSprings: proportions of the observable masses... VeNoo (talk) 22:02, 4 June 2013 (UTC)

Observers in a quantum mechanical context

Oh dear. I thought I'd bring myself up to date with thinking on the relevance of the observer in quantum mechanics but got to Observer (quantum physics) with its focus on human beings. I'd kick Capra right out but I don't know the current range of reasonable opinions. There is a welter of articles in this area and Quantum mind–body problem seems better to me but even there Dan Brown appears on-stage![2] To be fair he is dressed in new age robes. Also, Measurement in quantum mechanics starts off in a high-minded fashion but it looks like some sort of rot has maybe set in and at Measurement in quantum mechanics#Wavefunction collapse someone has inserted an extended editorial criticism of what is to follow. Can anyone with knowledge, energy and a sharp sword do anything about this? Thincat (talk) 12:01, 3 June 2013 (UTC)

I find it a tad strange that an article on the observer in quantum mechanics would fail to mention his importance in the various interpretations and place such undue emphasis on consciousness-driven collapse (without listing any interpretations that advocate it). Regarding the second article, I went ahead and moved the "editorial" comments to the talk page. I'm almost certain that, while the section could be clearer, it doesn't have any glaring errors, but what the comments boil down to is a (well-founded, to me) complaint that a lot of the formalism has been skipped/simplified. --Anagogist (talk) 15:31, 3 June 2013 (UTC)

Event (particle physics) and particle collision

The former is an unsourced stub for 8 years, which definitely is not good. The latter currently is a redirect to particle accelerator, which is plainly incorrect, because collisions occur not only in accelerators, but also with cosmic rays, during (or after) various nuclear reactions, and so. This unhealthy condition should be rectified, such that both items pointed to the same article. Incnis Mrsi (talk) 07:44, 4 June 2013 (UTC)

Agreed. I'll change particle collision to redirect to Event (particle physics) and have a go at expanding (including to just add sources) - it looks like half a dictionary definition, which is simply unacceptable. M∧Ŝc²ħεИ_τlk 14:27, 4 June 2013 (UTC)

Radiative symmetry breaking

I improved a bit the Coleman-Weinberg potential page (still the work needed, the CW potential doesn't even mentioned there as such...) and thought that it's a good idea to place more info on spontaneous symmetry breaking by radiative corrections not there but on the spontaneous symmetry breaking page or even make its own page (though I have less enthusiasm for the latter) VeNoo (talk) 21:27, 4 June 2013 (UTC)

New important article: Symmetry in quantum mechanics

Considering

• how painfully vague and unclear generators, groups, representations etc. are explained in the context of QM symmetries,
• there is some important content for relativistic quantum mechanics which couldn't fit into that article,

I wrote a summary style article in attempt

• to outline in plain language what the subject is about
  • hopefully explain some irritating and confusing notations,
  • clarify what is exponentiated and differentiated and Taylor expanded with respect to what...
• prevent riskfully damaging other articles trying to rewrite them,

allowing group abstractions to be furthered in main articles like

• representations of the Lorentz group,
• representation theory of the Lorentz group,
• generator (mathematics),
• all the other painful articles on group theory and group representations.

Also

• it parallels with symmetries in general relativity,
• last year there was concern about the opaqueness of group theory in QM here at this wikiproject.

There could be trillions of typos, and it needs more content added and more tightening up, which I can do in time anyway, but others are free to complain on the talk page as usual. One section completely absent is a section on gauge theories in QFTs, which is obviously critical for an article of this type.

So... before tearing it up to merge bits in other articles, or propose for deletion, or find any case for removing it in any way, or complaining "Maschen has created yet more mess for us to clear up" - please think first. Thanks. M∧Ŝc²ħεИ_τlk 00:38, 5 June 2013 (UTC)

It is not a small task you've taken on, but looks like a great start. Symmetry in quantum mechanics and QFT is a big subject, certainly big enough for a standalone article. Right now the article concentrates on continuous symmetries, but C, P, T, symmetry under particle exchange, supersymmetry and topological conservation laws (e.g., instantons) probably belong in there, too. Scale invariance and the renormalization group play a role in QFT, too. --Mark viking (talk) 03:25, 5 June 2013 (UTC)

Thanks for feedback, as always.

Yes, aware of and forgot to mention previously that particle exchange, isospin, C, P, T, symmetries, CP violation, the CPT theorem, Lorentz violation, which quantities/operations are conserved/preserved in which fundamental interactions, also need to be in there also. Even matter/antimatter is not mentioned.

Some things like supersymmetry are already mentioned but should be expanded on.

I don't know enough about the scale invariance/renormalization group, topological conservation laws, and instantons, so will leave that for those inclined and knowledgeable. M∧Ŝc²ħεИ_τlk 06:59, 5 June 2013 (UTC)

A great start on a vast subject. Xxanthippe (talk) 22:36, 5 June 2013 (UTC).

Stress tensor a DAB page?

Apologies if it's been raised before and caused irritation, but why is this a DAB page? It's an overall list of stress tensors. The variety of stress tensors combine with the momentum density of associated matter continua or fields into the relativistic stress-energy tensor, don't they? It would be helpful to link to this list without and let the reader see there is a list, considering that we're not supposed to link to DAB pages. Maybe even extend it into a very short summary style article describing the nature of stress tensors and what I just said (if correct). Thanks in advance. M∧Ŝc²ħεИ_τlk 15:04, 5 June 2013 (UTC)

The engineer who uses stress and strain tensors to model bridge flexure very much hopes that his bridge never enters the relativistic regime :-) More seriously, stress tensors are used in different contexts. In mechanics of materials, stress and strain tensors can for instance model the infinitesimal force and elastic deformation of a material object in equilibrium, where relativistic effects are negligible. In this application, there is no momentum. Since stress tensors are used in different ways in different fields (physics, civil, aeronautical and electrical engineering, etc.), disambiguation seems a reasonable thing to me. There are conceptual similarities among the stress tensors that could be described. The commonalities suggest that a DAB concept type article WP:DABCONCEPT could be appropriate. --Mark viking (talk) 16:07, 5 June 2013 (UTC)

I'll admit that was biased on relativity, but it could describe what you point out also, that applied engineers and theoretical physicists calculate with them. I picture a section titled "engineering applications" which has a brief overview and list of links, followed by another section "physics applications" briefly describing the relevant absorptions into a relativistic stress-energy tensor, or some similar structuring.

It may not work, since both applications will be intertwined. In any case, I'm not insisting on anything at all, just a suggestion.

Certain pages which look like DAB pages are also just lists like generator (mathematics). M∧Ŝc²ħεИ_τlk 17:25, 5 June 2013 (UTC)

Photon: a QED expert needed

Hello. I request a review of my edit [3].

First I became dissatisfied with parts of a previous version (which is slightly ambiguous and unclear) and posted to the talk page. Later I made my own effort to change it, but now I am equally dissatisfied with the result: all this explain mathematics, not physics. What can be done with it? Incnis Mrsi (talk) 17:46, 6 June 2013 (UTC)

Toroidal moment: fringe?

This article strikes me as being nonsense (or babble, of you prefer). Someone with more knowledge than I have should determine whether this should be deleted. — Quondum 01:30, 11 June 2013 (UTC)

If it is fringe, it is of a fairly mainstream sort. The cesium result was published in Science in 1997 and another article on anapole monents of protons was published in Science in 2000. The evidence in condensed matter is weaker, but there is still the CuO Science paper referenced in the article and a Cr2O3 paper in JETP, both by different research groups. Based on the sources, it looks pretty solid to me. --Mark viking (talk) 03:24, 11 June 2013 (UTC)

The first sentence in the article, "A toroidal moment is an independent term in the multipole expansion of electromagnetic fields besides magnetic and electric multipoles.", is clearly impossible. JRSpriggs (talk) 03:56, 11 June 2013 (UTC)

While the topic is solid from a source point of view, the article could definitely use some work. I agree that the first sentence as it stands, doesn't make much sense. One can break down currents and charges into longitudinal, poloidal and toroidal components and look at how these components play out in the multipole expansions. A nice exposition of this that seems reasonable to me at first reading is in the online article Complete electromagnetic multipole expansion including toroidal moments. There is a Physics Reports article, V. M. Dubovik, V. V. Tugushev “Toroid moments in electrodynamics and solid-state physics”, Phys. Rep. 187, 145-202 (1990). that I don't have access to at the moment, that probably goes into some detail as well. --Mark viking (talk) 04:50, 11 June 2013 (UTC)

Thanks for the input on this. So at least it seems that the concept (toroidal dipole/anapole) is receiving serious attention, and that appears to address something that may have been swept under the rug before. I may be off-beam, but the reporting on anapoles in Marjorana fermions may be a little overblown, but that's an separate topic. — Quondum 19:08, 11 June 2013 (UTC)

Marcelo Samuel Berman

I just removed a fresh string of new edits to Marcelo Samuel Berman, all based on a primary source and looking like wp:OR. Left warnings at User talk:187.59.21.11 and User talk:177.202.75.190. Can someone have a close look at what's going on there? Looks like a fan club. - DVdm (talk) 14:13, 11 June 2013 (UTC)

Long Hertzsprung Russell Diagram.jpg

image:Long Hertzsprung Russell Diagram.jpg has been nominated for deletion -- 65.94.79.6 (talk) 07:09, 14 June 2013 (UTC)

Stellar metamorphosis

Stellar metamorphosis has been nominated for deletion -- 65.94.79.6 (talk) 07:09, 14 June 2013 (UTC)

Differing Matter Content of the Milky Way Galaxy.png

Should image:Differing Matter Content of the Milky Way Galaxy.png be nominated for deletion ? Or should it be moved to commons? -- 65.94.79.6 (talk) 07:17, 14 June 2013 (UTC)

New (very short) article: Rate (particle physics)

This arose from event (particle physics). Do people think it should be merged anywhere? There must be far more to this quantity than what I wrote. I'll look around for more refs. M∧Ŝc²ħεИ_τlk 12:48, 5 June 2013 (UTC)

Cross section (physics) looks like a good place for it. There is little overlap and the concepts are strongly related. --Anagogist (talk) 10:00, 7 June 2013 (UTC)

I partially had that in mind also, just notifying in case someone had more to write about it (probably unlikely). If there are no objections anyone is free to throw it into the Cross section (physics) article in it's own section (with the sections of rate (particle physics) becoming subsections of course). Thanks, M∧Ŝc²ħεИ_τlk 16:27, 7 June 2013 (UTC)

I'll do this now. M∧Ŝc²ħεИ_τlk 12:41, 16 June 2013 (UTC)

New article: Spherical basis

I started it for now, it's relevant to this wikiproject because of spherical harmonics and quantum mechanics. It is incomplete and probably full of typos/inaccuracies, and I intend to finish it soon, but it's been sitting in my userspace for a very long time so for now it's been moved into mainspace allowing others the freedom to edit it, if inclined. M∧Ŝc²ħεИ_τlk 08:29, 12 June 2013 (UTC)

Content has been split from spherical basis to tensor operator, which as you all already know requires the formalism of spherical harmonics and QM, and has other applications. M∧Ŝc²ħεИ_τlk 12:41, 16 June 2013 (UTC)

New maintenance lists

I've been coding a bit, and the result is a number of new maintenance lists that might be of general interest:

• User:HhhipBot/Physics pages is a complete list of the pages within the scope of WikiProject Physics. It was originally inspired by our Index of physics articles series, but with some major differences: The list is divided (roughly) by field rather than the first letter of the page name, it includes hidden links to all talk pages, and it's automatically generated, thus low-maintenance. Its main purpose is to serve as an on-wiki project watchlist in combination with the Related changes feature, like this:

• general
• AMO
• applied
• condensed
• fluid
• particle
• theory
• bio
• pub/hist
• meta

• User:HhhipBot/Physics candidates is the same kind of list for articles that do not have a WP Physics tag, but are member of a tagged content category. In many cases this situation is justified, but there are many others where it would be worthwhile to check whether the article should actually get a project tag, whether it's in the right categories, and which of these categories should have a project tag.
• User:HhhipBot/Cleanup listing/Physics lists all physics articles that are tagged for cleanup, grouped by the type of cleanup needed. It's basically a copy of the cleanup lists generated by Svick's tool, but on-wiki, so it can be watchlisted and the article links are internal (that is, protocol-neutral). Bonus features are that each section can be individually transcluded, and several ways to find new or recently resolved issues.

The underlying code is still under development, but ready for some beta-testing. At the moment the bot is only run supervised, the long-term plan is to run it automatically about once a week. Comments and suggestions are welcome! — HHHIPPO 12:08, 16 June 2013 (UTC)

Very good work which is not neglected. Thanks for your efforts! M∧Ŝc²ħεИ_τlk 12:26, 16 June 2013 (UTC)

EarlyTeslaCoil.PNG

image:EarlyTeslaCoil.PNG has been nominated for deletion -- 65.94.79.6 (talk) 00:41, 17 June 2013 (UTC)

Dilation as field (DaF): fringe alert

A piece of non-academical (or marginally academical) science, partially based on works of a fringe scientist Piotr Ogonowski. FYI I attended on one his presentation, tried to communicate with him, so I really know what I said. Incnis Mrsi (talk) 08:02, 17 June 2013 (UTC)

This seems to be almost entirely the work of Gigantmozg (talk · contribs) who has been adding links to it from other articles. JRSpriggs (talk) 12:11, 17 June 2013 (UTC)

I have removed the mention in Time dilation. There's more (see Special:Contributions/Gigantmozg), but I'll leave those to others. - DVdm (talk) 13:36, 17 June 2013 (UTC)

Ironically, I did not notice that Gigantmozg is (a bit shortened) transliteration for “giant brain” in Russian. Was Ogonowski’s visit to Moscow a month ago purely coincidental? Incnis Mrsi (talk) 15:32, 17 June 2013 (UTC)

Help needed at WP:AfC

Hello, can anyone give this article a glance over Wikipedia talk:Articles for creation/Asymptotic Safety, firstly to check if it's not some common physics joke, and secondly to check if it makes sense. I think the opening paragrph could use re-writing in plainer English, but recognise we have to document complex stuff sometimes. Any help with this appreciated Rankersbo (talk) 18:31, 18 June 2013 (UTC)

It's not a physics joke. I think the idea of a nonperturbative fixed point as a fix for perturbative non-renormalizability of quantum gravity was proposed by S. Weinberg, a prominent physicist, but proving that this fixed point exists is a difficult exercise. Such an approach was already mentioned at Ultraviolet fixed point#Asymptotic safety scenario in quantum gravity It should be asymptotic safety, not Asymptotic Safety. The author seems quite keen; they have already created the associated article Physics applications of asymptotically safe gravity outside AfC. I agree that the lead para could be written more simply and with more context. This review of asymptotic safety in quantum gravity is fairly extensive and provides a nice secondary source for the topic. --Mark viking (talk) 19:05, 18 June 2013 (UTC)

Hello. As I'm the author of Wikipedia talk:Articles for creation/Asymptotic Safety, I shouldn't comment on its scientific correctness. Nevertheless, I have some questions/comments. 1.) Is it possible to change the title? The term "Asymptotic Safety" can be applied to many areas in physics, while the article mainly concerns quantum gravity. So I propose the title "Asymptotic Safety in quantum gravity". 2.) The term "Asymptotic Safety" has usually been capitalized in the literature. However, since many journals insist in lowercasing, now both versions "Asymptotic Safety" and "asymptotic safety" are common. I could change it, although I prefer the capitalization. 3.) I highly welcome any suggestions for rewriting some sentences of the opening paragraph in plainer English, however, without altering the content. 4.) Concerning the article Physics applications of asymptotically safe gravity: What does it mean if an article is created outside AfC? Can it be moved to AfC? --&reasNink (talk) 09:12, 19 June 2013 (UTC)

Hi &reasNink, welcome and thanks for writing these articles. It's fine for you to comment on an article you wrote. Although it may seem like it, we are not here to pass judgement--ideally it is more of a conversation among editors. In answer to your questions, yes it is possible to change the title of the article, both in the transition from AfC or after the article has been created. According to the Wikipedia Manual of style WP:MOS, article title should use sentence case, so the new title should be "Asymptotic safety in quantum gravity". I proposed using asymptotic safety in the body of the article because the topic seemed more like a generic concept, like asymptotic freedom, than a proper noun. It is also fine to for you to have created Physics applications of asymptotically safe gravity outside the AfC process. It is just that new editors often wait for their first article to get through AfC before creating other articles. But you did nothing wrong. --Mark viking (talk) 10:34, 19 June 2013 (UTC)

Hi Mark viking. Thanks for your answer! You convinced me to use the lowercase version "asymptotic safety" (unlike most articles in the literature) globally in the article. So can somebody change the title to "Asymptotic safety in quantum gravity"? (I don't know how this can be done...) I apologize for the beginner's mistakes I commit! --&reasNink (talk) 12:29, 19 June 2013 (UTC)

Wikipedia talk:Articles for creation/Asymptotic Safety

Resolved

Can someone give Wikipedia talk:Articles for creation/Asymptotic Safety a technical review and see if there is any reason it shouldn't be summarily accepted as an article? You can add commentary to the top by using the {{afc comment}} template (subst: not required, contrary to any documentation that says otherwise). davidwr/(talk)/(contribs)/(e-mail) 03:22, 19 June 2013 (UTC)

At the top of the page between the "history" tab and the "watch"/"unwatch" tab, there should be a "move" tab. Moving the article is how one changes its name. Of course, you will then have to edit the lead sentence accordingly. Check the "what links here" in the toolbox and edit any redirected redirects to link directly to the article by its new name. JRSpriggs (talk) 15:32, 19 June 2013 (UTC)

Note also that it should move to Asymptotic safety (Sentence case) and not Asymptotic Safety (Title Case). Andy Dingley (talk) 15:36, 19 June 2013 (UTC)

As the first of these is already a bluelink, a simple move like this may fail (as there's already another page in the way). You might need to ask an admin to move it for you - see WP:RM, or else ask back here. Andy Dingley (talk) 15:39, 19 June 2013 (UTC)

Andy: Re: sentence case - thanks. I'm aware of the blue-link and the procedure for handling it. davidwr/(talk)/(contribs)/(e-mail) 23:01, 19 June 2013 (UTC)

Actually, I was looking for a critique of the content: is it scientifically accurate and is it NPOV, or are there content-related reasons to not move it? davidwr/(talk)/(contribs)/(e-mail) 23:01, 19 June 2013 (UTC)

Thanks for the input. The article has been accepted and renamed. It is now at Asymptotic safety in quantum gravity. davidwr/(talk)/(contribs)/(e-mail) 23:54, 19 June 2013 (UTC)

Spin matrix (and plural: spin matrices)

This term could refer to a number of things, so I created a DAB page. The plural spin matrices used to redirect to Pauli matrices, so I'll remove double redirects from articles, to spin matrices, to Pauli matrices. If anyone disagrees with a DAB page and there is widespread consensus to redirect it somewhere, we could overwrite the spin matrix and spin matrices towards Pauli matrices, presumably. M∧Ŝc²ħεИ_τlk 22:12, 20 June 2013 (UTC)

Alternatively, it may redirect to a relevant section in spin, if someone is willing to make it. Redirect to Pauli matrices is certainly worse, because they describe only non-relativistic spin (or the spin of a massive particle in its center-of-momentum frame), and are focused on the spin ½. Incnis Mrsi (talk) 09:27, 22 June 2013 (UTC)

As I understand it, the term usually means matrices used to represent 'vector-like' basis vectors of a Clifford (or geometric) algebra. The first such matrices were the Pauli matrices, also called the Pauli spin matrices, hence the general term "spin matrix" (even though the matrices may have rather little to do with spin necessarily). The matrices give a basis for bivector methods for representing rotations and/or hyperbolic rotations, depending on the signature of the space. Other articles we have in this area, as the dab page indicates, include Gamma matrices, Generalizations of Pauli matrices, and Higher-dimensional gamma matrices. "Spin matrices" as a term is perhaps unfortunate, as often the relevance of these matrices in a particular setting has very little to do with physical spin. Nevertheless, the group for which they provide a representation is called the Spin group, and Spin matrix does seem to be the widely used term.

The other entries on the page -- viz Wigner D-matrix and Higher spin alternating sign matrix -- are rather different things, and I am not sure that they ever are in fact referred to as "spin matrices". Jheald (talk) 14:22, 22 June 2013 (UTC)

Well, Higher spin alternating sign matrix is a matrix with the term "spin" in the name, and the Wigner D-matrices are used in the context of angular momentum, so thought to include them for an increased scope. Maybe we could just place those two under a "see also" section, at least.

A redirect to spin (physics) or a section in that article isn't a bad idea, but this is now linked from the DAB page allowing readers to access the article if needed. M∧Ŝc²ħεИ_τlk 16:22, 22 June 2013 (UTC)

Who are the famous quantum mechanists?

Probably a sticky discussion, but where do we draw the line with contemporary quantum physicists in Template:Quantum mechanics? A couple draw my immediate attention as being both alive and not in possession of a Nobel prize:

• F. J. Duarte - I've not heard of him before. Not my field, perhaps. The article on him reads a bit like a CV at the moment.
• Anton Zeilinger - In the popular press is said that he is working on demonstrating foundations of quantum mechanics, although I'm not directly familiar with his work.

There are also a variety of people who won Nobel prizes in things related to QM... but everything is QM, (for starters, Blackett, Shockley, von Klitzing, Störmer, Tsui, Laughlin). If they are included, there are so many more Nobel prize winners in the same category, that should be added. I don't mean to put down these peoples' work, it's just that the list of names is getting long. Perhaps instead of "Scientists" we could just put "Founders". --Nanite (talk) 00:04, 21 June 2013 (UTC)

Yes, only include in the template those who founded the formalisms used in QM, and proposed important philosophical implications, would seem like the best scope. M∧Ŝc²ħεИ_τlk 07:27, 21 June 2013 (UTC)

Anton Zeilinger is well known in the field of quantum information. So, perhaps one needs to create a category for this and related fields. People like Anton Zeilinger, Wojciech Zurek, Dieter Zeh, Lev Vaidman etc. stand out from the average physicists working in quantum mechanics related fields and should be included in an appropriate category. Count Iblis (talk) 23:10, 21 June 2013 (UTC)

I agree we should have clear inclusion criteria for this and similar templates, both to make the lists easier to maintain and to make them more meaningful for readers. I'm not completely convinced that 'Founders' is the answer though, in fields that develop over a long time there might be important contributions that came later. Either way, we should find a general consensus, keep the results somewhere quotable (e.g. at WP:MOSPHYS), and maybe link 'Scientists', 'Founders', 'Contributors' or whatever it will be in the templates to that definition. This general rule could still be overridden on individual templates by local consensus, but nothing less than that. One could also think about reserving some space in <noinclude> tags or on the template's talk page, where reasons for individual inclusions can be documented and referenced if needed. — HHHIPPO 11:15, 22 June 2013 (UTC)

Goethe-Prism-FigIIc.jpeg

file:Goethe-Prism-FigIIc.jpeg has been nominated for deletion -- 65.94.79.6 (talk) 07:03, 21 June 2013 (UTC)

Speaking of Duarte ... self promotion?

Something was bugging me about seeing F. J. Duarte listed among the giants of quantum mechanics (see above). (added here, "adding physisists that contribuited with something new in quantum physics") The article about him, which reads like a CV, seems to be edited mostly by User:Northryde and Special:Contributions/66.195.235.242 (University of Rochester). Northryde is also often editing articles on John Clive Ward and his quotes; Ward was one of Duarte's advisors. The IP address editor removed a Talk topic regarding the notability of the article on Duarte. There is also an enormous Wikiquotes page on Duarte [4], which is mostly edited by IPs 66.195.235.242, 128.151.39.* (University of Rochester). Another account that appears to be related to this circle is Corrigendas.

Many of the edits refer as a source to books written by Duarte or to the website Optics Journal, such as a memoir on Ward written by Duarte; Optics journal is based in Rochester and appears to be closely related to Duarte, likely owned by him (the domain is his). I'm new to wikipedia and this project — is this the point where one concludes it is self-promotion?

--Nanite (talk) 19:56, 21 June 2013 (UTC)

Update: I'm quite sure now this is promotion of some sort... many pages are loaded with Duarte references with undue weight. Duarte's work may be valid but it seems to be extremely specialized and I'm not sure whether it merits inclusion on WP. The edits by Corrigendas are the most prolific, recently. I invite you to take a look, they are too numerous for me to list all of them, but here is a sample:

• Beam expander: Should be mostly about telescopic beam expanders (what opticians actually use, see Edmund optics), but instead is all about Duarte's favourite topic, N-slit interferometry.
• Polarization rotator: Same beef.
• Spider web: Random inclusion of paper by Duarte (a paper notable for being cited ... once, by himself).
• Willis Lamb: Corrigendas lets us know what Duarte thinks of Lamb. The Rochester IPs earlier added a photo of Duarte and Lamb.
• N-slit interferometer: Uhhh... Fraunhofer diffraction anyone?

--Nanite (talk) 10:45, 22 June 2013 (UTC)

Higgs boson is scalar with a spin of 0?

Please forgive me for being dumb here but I was just wondering why the newly updated chart at http://en.wikipedia.org/wiki/Standard_Model and http://en.wikipedia.org/wiki/File:Standard_Model_of_Elementary_Particles.svg states that the Higgs boson has a spin of 1. I thought the Higgs boson was a scalar and had a spin of 0. — Preceding unsigned comment added by 69.179.5.5 (talk) 15:55, 20 June 2013 (UTC)

Probably just a mistake when it was being redone. I brought it up on the commons page. Laura Scudder | talk 16:09, 20 June 2013 (UTC)

thanks, do you have a link to the commons page where you posted, i can't find it i'm new at wikipedia — Preceding unsigned comment added by 69.179.5.5 (talk) 18:06, 20 June 2013 (UTC)

There's a box right below the image in your second link that says, "This is a file from the Wikimedia Commons. Information from its description page there is shown below." That's how you can find the page where the file is hosted at commons. But you'll notice that the spin has already been fixed. Laura Scudder | talk 19:18, 20 June 2013 (UTC)

thank you! — Preceding unsigned comment added by 69.179.5.5 (talk) 15:11, 23 June 2013 (UTC)

Wikipedia talk:Articles for creation/Ferroelectric crystals

I'm not sure if this is the correct Wikiproject for this, but I am wondering if Wikipedia talk:Articles for creation/Ferroelectric crystals is distinct from the various other articles about ferroelectric this and that, or whether it is a duplicate term? —Anne Delong (talk) 11:22, 22 June 2013 (UTC)

Seems redundant compared to Ferroelectricity, IMO. M∧Ŝc²ħεИ_τlk 08:53, 23 June 2013 (UTC)

New article: Arthur Komar

Similar story to the above. Apparently A. Komar was influential in general relativity research.

We have to be careful on the full name, two names which appear in search engines are "A. J. Komar" and "A. B. Komar" and seem to be the same person (possibly "A.J.B.Komar" or "A.B.J.Komar"?), but I could be wrong, if they are the articles and content should be split.

If those with interest in the history of general relativity, or scientists in general, are able to verify anything when they have time and inclination, I would be extremely grateful in advance. Cheers, M∧Ŝc²ħεИ_τlk 08:51, 23 June 2013 (UTC)

Arthur J Komar looks like a different person. --Mark viking (talk) 16:39, 23 June 2013 (UTC)

Thanks for pointing that out, I didn't look far enough, I'll remove the music book reference to A.J. Komar. M∧Ŝc²ħεИ_τlk 17:05, 23 June 2013 (UTC)

Fermi energy

The Fermi energy article has undergone some changes recently. For example the first sentence now says, "The Fermi energy is a concept in quantum mechanics usually referring to the energy difference between the highest and lowest occupied single-particle states".

Before the most recent changes (10 May to 20 June), the first sentence use to say, "The Fermi energy is a concept in quantum mechanics usually referring to the energy of the highest occupied quantum state in a system of fermions at absolute zero temperature, where all states below are occupied and all above are empty".

To me there is a difference. Unfortunately, I am not finding many available sources that specifically describe "Fermi energy" so I can't tell which description is accurate.

Also the term "chemical potential" has been changed to "electrochemical potential" throughout the article, and I don't know if this matters. I am hoping someone with a deep enough background can have a look at this article, its recent changes, and verify the article's accuracy. Thanks. ---- Steve Quinn (talk) 14:36, 24 June 2013 (UTC)

I agree with the older formulation. Energy cutoff at absolute zero. JRSpriggs (talk) 14:41, 24 June 2013 (UTC)

Here's a page from one textbook at Google books: [5]

It defines E_F using the Fermi-Dirac distribution, as the energy where the occupation probability falls to 0.5

At absolute zero this probably does indeed correspond to "the highest occupied quantum state in a system of fermions", per the old definition; but two caveats appear to be needed:

(i) According to the text-book page "The Fermi energy... depends on temperature, but the dependence is weak for metals

(ii) See the discussion section Talk:Fermi_energy#Chemical_Potential_.3D_Fermi_Energy_at_0K.3F on the article talk page: for a semiconductor this quantity in the limit T -> 0 may be in the middle of a band gap, and so not an occupied state at all.

The previous talk-page section Talk:Fermi_energy#Fermi_energy_in_semiconductor also suggests that identifying the parameter with the quantity in the FD distribution at all temperatures, is a far from universal definition; with several respected books instead identifying the term exclusively with the zero-temperature limit.

The claim though that it is the relative energy difference between "the highest and lowest occupied single-particle states" seems utterly unfounded however. Jheald (talk) 14:59, 24 June 2013 (UTC)

For the record, here's the IUPAC Gold Book on the subject: "Fermi energy:The total energy of an electron in an uncharged metal at the Fermi level."[6] -- so not a relative energy; and not necessarily at absolute zero. Jheald (talk) 01:55, 25 June 2013 (UTC)

Yeah, this is a topic that's been debated many times (namely, whether Fermi level and Fermi energy are the same thing, absolute zero vs finite temperature, total vs. kinetic energy, etc.). The concept you are referring to is well described on the page Fermi level, and indeed many people refer to that concept when they say "Fermi energy". You read the talk page of Talk:Fermi_energy already, but also take a look at the talk page of Talk:Fermi_level for even more discussions along this line (Steve made a nice table here). The reason I clarified the Fermi energy article is that, before I started editing it, all the material on that page gave expressions for Fermi energy with zero energy defined to be the state of zero kinetic energy. See the bottom examples, where specific numbers for the Fermi energy are given. To be totally honest, I'm not satisfied with the article, either.

You just gave me an idea, though. Most of the discussion on the Fermi energy article is about idealized Fermi gases (as in, a very basic approximation trying to describe metals, white dwarfs, etc.), and so it would probably make sense to move that discussion over to Fermi gas. The Fermi temperature would then redirect there as well (definitely, Fermi temperature can only be defined in terms of kinetic energy, not total energies where the zero is defined flexibly). Possibly, this would leave so little material that we could then make Fermi energy a disambiguation (→Fermi level for the electrochemical potential of electrons at finite temperature, as in your definition, →Fermi gas for the kinetic energy at zero-temperature, for idealized non-interacting fermions). What do you think? --Nanite (talk) 10:15, 26 June 2013 (UTC)

Harrassment and bullying at Wikipedia?

In the last couple of day a fury of comments and link deletions generated from a user named Nanite have affected articles that reference work by Duarte. Even one of the figures appearing in N-slit interferometer and N-slit interferometric equation has been corrupted and rapidly proposed for deletion while one of these articles has been proposed for a "merge."

Many of us have come to Wikipedia with the best intentions and to contribute in good faith. I have contrubuted to many biographies and articles and never have I even contemplated attacking anyone. This type of agressiveness and ciber violence should have no place in Wikipedia. Some of the allegations made by Nanite in this page are quite contentious. Let us remember that according to Wikipedia policy "contentious material about living persons must be removed immediately."

The biography of Duarte is well referenced to the peer review literature and includes a good number of third party references which is exactly what Wikipedia requires. Also the Wikipedia article is quite different from the CV that appears at his web site or other professional web sites. Example of carelessness in Nanite's comments: The entry of Duarte as a "founder of quantum mechanics" was immediately flagged by me as a mistake with the following comment: "On August 2, 2012, more than 100 unconnected links (to articles where FJD is not mentioned) were added to this page either by mistake or misdirection Northryde (talk) 11:38, 3 August 2012 (UTC)"

Bullying should have no place in Wikipedia. Northryde (talk) 19:48, 24 June 2013 (UTC)

Duarte: "founder of quantum mechanics"

After looking at the record (August 2, 2012), the day that Duarte was entered as a "founder of quantum mechanics" there were several edits made to that page by two editors: RockMagnetist and Gdrg22, who wrote "adding physicists that contributed with something new in quantum physics." Is one of these editors Duarte himself? or Do they know him? I doubt it. This little exercise demonstrates the carelessness and falsehood behind the conjecture floated by Nanite (talk). The behavior of Nanite unnecessarily damages Wikipedia and his editing privileges should be revoked.Northryde (talk) 23:46, 24 June 2013 (UTC)

I don't think anyone would think that. Those users generally make a wide diversity of edits on various topics while citing various sources by different people, unlike User:Corrigendas and yourself. Speaking of which, where is Corrigendas? I left a note on that user's talk page linking to here, and yet you are the one responding (my apologies by the way, I had meant to also leave a note on your page).

If you have a problem with my edits, please let me know. I am actually quite curious what is the difference between an n-slit interferometer and a regular diffraction grating, and if you clarify that then I don't see any reason to merge. --Nanite (talk) 07:56, 26 June 2013 (UTC)

Let's recap: this whole thing began when the user Nanite got upset at Duarte being listed in the "scientists" section of quantum mechanics. Now we know that this was done by either RockMagnetist or Gdrg22 (August 2, 2012) and that I had absolutely nothing to do with it. Furthermore on August 3,2012, when I noticed the large increase in the number of links to the Duarte article I questioned it using the words "mistake" and "misdirection."

Next, on this page, Natite writes a whole section about self promotion including me (June 21, 2013) and sends me a note. However, Nanite expresses surprise about my response on this page: "and yet you are the one responding" Nanite (07:56, 26 June 2013). This indicates to me that Nanite is somewhat detached to even recent reality, or simply careless.

Finally Nanites asks a question: "what is the difference between an n-slit interferometer and a regular diffraction grating." Now, that is a question that could have been asked directly without the unnecessary antagonism surrounding this whole thing. I guess that an answer to that question is that (1) a grating is a passive optical element while an n-slit interferometer (NSI) is an active electo-optical instrument including a digital detector; (2) a transmission grating is just a component of the NSI.

Finally, I won't dedicate more time to this matter.Northryde (talk) 13:25, 27 June 2013 (UTC)

Hold on a second, I never sent you any note, I sent one to Corrigendas. Are you saying that you are using two accounts on wikipedia? That's generally a bad idea on wikipedia, and can get you into trouble.

Thanks for misrepresenting everything I said and ignoring the main point, being that: you, Corrigendas, and certain Rochester IP addresses make edits exclusively concerning Duarte and Duarte's friends (their research topics and their personal life details). In any case, I'm glad you are now warned and aware of the policies regarding conflict of interest on wikipedia, so the point is made. I'm sure that if there is a continued problem in the future, then someone will notice and bring it to the attention of the applicable noticeboard. Goodbye. --Nanite (talk) 18:03, 27 June 2013 (UTC)

This discussion is especially boring because neither side is not willing to present any links (WP:DIFFs or whatever) but rather useless “User:”: there are only eloquences, copy-and-pasted chunks of text, and quotation marks. FYI the use of two accounts is not generally discouraged, but the use of two accounts for working on the same article is certainly a bad idea. Incnis Mrsi (talk) 18:21, 27 June 2013 (UTC)

This is the message sent to me and the reason I learned about this page:

Nanite mentioned you on Wikipedia talk:WikiProject Physics."→‎Speaking of Duarte ... self promotion?: new section" 21 June

Now, Nanite claims he did not send this message, but obviously someone did.Northryde (talk) 16:28, 28 June 2013 (UTC)

Northryde, the "message" you're referring to could be the notifications that appear in the top-right next to your user name link, where the number is. No one sends those notifications, they're automated. Indeed Nanite has never posted on your talk page, but did on Corrigendas's page [7][8]. The only other way I can think of would be email from someone (?). M∧Ŝc²ħεИ_τlk 18:17, 28 June 2013 (UTC)

The light, visible

Visible light (edit | talk | history | protect | delete | links | watch | logs | views) and Visible Light (edit | talk | history | protect | delete | links | watch | logs | views) are under discussion at WP:RFD -- 65.94.79.6 (talk) 11:25, 29 June 2013 (UTC)

Exchange symmetry

What to do with this article? It's rather short, and could be

• expanded, or
• split to elsewhere like identical particles, or
• since it's about symmetry in quantum mechanics I'd (naturally) be inclined to just merge it into that article.

Others may have a different opinion. Raised this at talk:Exchange symmetry. Thoughts? M∧Ŝc²ħεИ_τlk 08:52, 30 June 2013 (UTC)

Followed up at talk:Exchange symmetry. Jheald (talk) 15:40, 30 June 2013 (UTC)