Wikipedia talk:WikiProject Physics/Archive October 2008

Help needed at Neutrino

Two questions need to be answered on the Neutrino talk page, that are beyond me:

1. Should the estimated mass be put in the infobox?
2. Are anti-neutrinos and neutrinos possibly the same particle?

Thanks! -Ravedave (talk) 03:32, 1 October 2008 (UTC)

Wikipedia 0.7 articles have been selected for Physics

Wikipedia 0.7 is a collection of English Wikipedia articles due to be released on DVD, and available for free download, later this year. The Wikipedia:Version 1.0 Editorial Team has made an automated selection of articles for Version 0.7.

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Just my $.02 opinion here, but shouldn't the list of articles getting top priority be pruned back a bit to just a core list? I am curious to know why, for example, sun, star, nature, telescope, heliocentrism, stellar evolution, biophysics, atmospheric physics, geophysics, Galaxy formation and evolution, Solid angle and Molecular orbital ranked as top. Why is Uranium top but not Plutonium or Radioactive decay? Do that many physicist articles really need to be top ranked? Why is Archibald_Hill ahead of Archimedes? Why is Refraction high but Diffraction top? Kelvin is top, but then why is hertz or Joule only high? Why top for Electrical resistance but high for superconductivity? Wow! signal has a mid rating in Physics?!? The list seems somewhat inconsistent and top heavy. Thanks.—RJH (talk) 20:51, 22 September 2008 (UTC)

Top heavy? Have you actually looked at the actual distribution? Out of the the nearly 5000 physics articles with an importance rating only 290 have a top rating and 908 are rated high. (low and mid have about 1500 each, and there are still about 5000 article that need to be rated most of which should probably get a low or mid rating) So, I don't think you can say the ratings are top heavy. If anything we are a bit "top-light"

Fair enough. It was just a superficial observation.

I agree that some of the top ratings are odd such as sun which in my view is not a physics article at all.

Perhaps the intent was to include Solar neutrino? But that shouldn't be top I would think.

Others are there because of specific criteria: I think all SI base units are currently ranked as top (this explains Kelvin and Solid angle. So, should be all major subfields. (which explains the ratings for biophysics and geophysics.

You make a good case for further sharpening the importance guidelines. (TimothyRias (talk) 08:56, 23 September 2008 (UTC))

Thanks.—RJH (talk) 20:54, 24 September 2008 (UTC)

Out of interest the Schools Wikipedia list is here. Proportionally science is a much high proportion of the Schools WP, including the Physics PortaL and comments on that list would be very welcome. --BozMo talk 11:37, 2 October 2008 (UTC)

Atomic nucleus and Nuclear physics

I'm sorry I didn't see the reader comment that the contents of Nuclear physics and Atomic nucleus could and should be basically switched with vast improvement to both articles. There's actually a template that suggests this, which we can put on both articles for awhile, or we can just be WP:BOLD and DO it, since we've had no comment to your TALK suggestion. Let me know. And thanks for noticing this gaff. The article on Atomic nucleus should be about the THING. The article on nuclear physics should be about the branch of physics that studies that thing. As it is, if you read these articles, they are basically reversed from that ideal. I propose that as a first stage in fixing this, we switch their contents, then clean up from there. What say you all? SBHarris 21:26, 2 October 2008 (UTC)

Organisation of articles on orbitals / atomic / molecular strutcure

I have added comments to Electron configuration (at Talk:Electron configuration#Redundancy with other articles) and Electron cloud (at Talk:Electron cloud#Merger proposal) commenting on redundancy and bad organisation of e.g. Atomic orbital, Electron cloud, Molecular orbital theory, Molecular orbital, but now I realise it is really a job for this project (for which I regret to say I have neither time nor expertise). PJTraill (talk) 14:25, 3 October 2008 (UTC) (anchor added PJTraill (talk) 14:26, 3 October 2008 (UTC))

Perhaps Wikipedia talk:WikiProject Chemistry would be more interested? JRSpriggs (talk) 16:12, 3 October 2008 (UTC)

I wouldn't know, I think I saw that one of the articles fell under this project. PJTraill (talk) 17:38, 3 October 2008 (UTC)

Both Atomic orbital and Electron cloud were tagged only for the Physics project and should be in the Chemistry Project also. I have fixed that. JRSpriggs is absolutely correct. This discussion should primarily be at the Chemistry Project. I will do that. Bduke (talk) 23:19, 3 October 2008 (UTC)

Relativistic mass distortion‎

I've proposed that article for deletion. Please comment at Wikipedia:Articles for deletion/Relativistic mass distortion‎. --D.H (talk) 20:50, 3 October 2008 (UTC)

Quark at FAC

Concern has been expressed that domain experts have not reviewed Wikipedia:Featured article candidates/Quark. SandyGeorgia (Talk) 19:53, 4 October 2008 (UTC)

conversions of tables to orbit diagrams

A discussion at Talk:Gliese 581 c revolves around the OR-ness of converting data tables to diagrams of orbits. This might be of interest to you. 70.51.8.75 (talk) 08:56, 6 October 2008 (UTC)

Cadmium telluride photovoltaics

User:SolarUSA (Talk, Contributions) posted the article Cadmium telluride photovoltaics today. It's a shameless advertisement for the First Solar corporation, but has too much good content to outright delete (IMO). If someone wants a big clean-up project, here it is. I think it has the potential to eventually be a very nice article on an important topic. :-) --Steve (talk) 02:30, 10 October 2008 (UTC)

FYI Centrifugal force (planar motion) at AfD

Centrifugal force (planar motion) was sent for deletion at WP:AFD 70.51.10.188 (talk) 04:20, 11 October 2008 (UTC)

Maybe we'll figure out if WP:FICT applies to Fictitious forces... --Falcorian ^(talk) 07:20, 12 October 2008 (UTC)

Does that mean we need to slap {{in-universe}} on everything in this project except Many-worlds interpretation? - Eldereft (cont.) 17:36, 12 October 2008 (UTC)

Tensor equivalent of Dirac equation

As you know, the Dirac equation is invariant under Lorentz transformations, but not (without modification) under the arbitrary curvilinear coordinate transformations used in general relativity. I have seen texts which purport to generalize spinors to transform under such coordinate transformations. However, they are very hard to understand and I am not convinced that they work. Even if they do, it is not clear to me why it should be necessary to go beyond the formalism of tensors and tensor densities. Google gave a few papers mentioning a "tensor Dirac equation". One of them claimed to have proven that the wave function could be represented as a vector provided that the gamma matrices were replaced by rank 3 antisymmetric tensors (or some such, it was not very clear). Does anyone know more about this subject? JRSpriggs (talk) 20:29, 10 October 2008 (UTC)

Some original research on my part yields a tensor Lagrangian which I think should be equivalent to the Dirac equation. The spinor, $\psi \,,$ is replaced by a sequence of antisymmetric tensors of every rank from 0 to 4, thusly

$\psi =(\psi ^{(0)}\mathbf {1} +\psi _{\alpha }^{(1)}\gamma ^{\alpha }+\psi _{\alpha \beta }^{(2)}\gamma ^{\alpha }\gamma ^{\beta }+\psi _{\alpha \beta \gamma }^{(3)}\gamma ^{\alpha }\gamma ^{\beta }\gamma ^{\gamma }+\psi _{\alpha \beta \gamma \delta }^{(4)}\gamma ^{\alpha }\gamma ^{\beta }\gamma ^{\gamma }\gamma ^{\delta })\,\xi \,$

where ξ is a constant spinor. The Lagrangian is then

$L=({\frac {1}{2}}mc^{2}(\psi ^{(0)}\psi ^{(0)}+\psi _{\alpha }^{(1)}g^{\alpha \beta }\psi _{\beta }^{(1)}+\ldots +\psi _{\alpha \beta \gamma \delta }^{(4)}g^{\alpha \epsilon }g^{\beta \zeta }g^{\gamma \eta }g^{\delta \iota }\psi _{\epsilon \zeta \eta \iota }^{(4)})\,+\,$

$i\hbar c(\psi _{\alpha }^{(1)}g^{\alpha \beta }\partial _{\beta }\psi ^{(0)}+\ldots +\psi _{\alpha \beta \gamma \delta }^{(4)}g^{\alpha \epsilon }g^{\beta \zeta }g^{\gamma \eta }g^{\delta \iota }\partial _{\epsilon }\psi _{\zeta \eta \iota }^{(3)}))\,{\sqrt {-g}}\,$

where the constant factors may need some adjustment, and the partial derivative could be replaced by the gauge covariant derivative to link it to electromagnetism. Unfortunately, as OR, I cannot put this in an article. But if (as is highly probable) someone else has done essentially the same thing and published it, then we just need to find the reference and then we can have an article on it. It would be useful as a demonstration that spinors are non-essential and in showing how the electron can be handled in the context of general relativity. JRSpriggs (talk) 02:40, 12 October 2008 (UTC)

One commmon way to implement a covariant Dirac equation is discussed on page 29 and further of [1], which are lecture notes of a grad level cosmology course at Utrecht University. This approach uses the vierbein formalism for GR. (TimothyRias (talk) 08:44, 13 October 2008 (UTC))

Harry Lipkin article

Hi, I'm from the self-importantly named Guild of Copyeditors and have just been working on Harry J. Lipkin. The article had been created by running the German equivalent through BabelFish, and took a lot of deciphering. I've knocked most of the biographical stuff into shape but found the sections on Lipkin's research in physics incomprehensible, and have moved them to the article's talk page. Could someone here take a look and see if sense can be made of it? Better still if you can read German - the original's here and may help you figure out what the article should have said. Many thanks. Gonzonoir (talk) 14:24, 13 October 2008 (UTC)

Matter

Could someone head over at matter and expand the section on solid/liquid/gas/plasma. I'm having a brain fart and I can't write short an accessible definitions. Headbomb {ταλκ – WP Physics: PotW} 07:35, 14 October 2008 (UTC)

Antisymmetric wave function image?

By any chance does somebody have a good example of an antisymmetric wave function I could use in Wikipedia (to represent the interaction of two identical particles)? I saw this image on the commons, but it is for a particle in a 2-D box. Thank you!—RJH (talk) 20:56, 24 September 2008 (UTC)

Should be easy to make. What exactly are you looking for? (TimothyRias (talk) 10:25, 25 September 2008 (UTC))

Thank you. Perhaps an antisymmetric wave equation corresponding to the probability distribution shown here: http://rugth30.phys.rug.nl/quantummechanics/idpart.htm#Fermions —RJH (talk) 20:27, 27 September 2008 (UTC)

That would be difficult since that is a 2D system, making the two-particle wavefunctions 4D, which is hard to depict. This means we will be stuck with 1D systems. So what will it be: infinite well or harmonic oscillator?

Furthermore, the resulting 2D functions can be plotted as either a contourplot or as a 3D plot. Do you have a preference? (TimothyRias (talk) 15:08, 29 September 2008 (UTC))

How about something like this

The left picture is a contour plot of the asymmetric ground state for two particle in a 1d box. The right picture is the corresponding symmetric wave function of the same energy. These are rough versions, I can tweak them further if this is the sort of thing you were looking for. (TimothyRias (talk) 12:46, 1 October 2008 (UTC))

That looks good, except the second image just looks like the first after a rotation. Is there any possibility of a 3-D projection of your first image as in the 2D Wavefunction? That might help a reader get the picture, so to speak.—RJH (talk) 19:22, 1 October 2008 (UTC)

Sure, but I will be away for a couple of days si it i'll have to wait till next week. (Note that even in a 3D projection the second will look like a 90 degree rotation of the first, because coincidentally it happens the be one.) (TimothyRias (talk) 06:06, 2 October 2008 (UTC))

Okay thanks. However, I don't think it will be too helpful if the symmetrical and antisymmetrical wave functions essentially look identical.—RJH (talk) 20:35, 4 October 2008 (UTC)

Attempt 2:

(again this is a draft version, I can fine-tune the formatting if this is to your liking. In this case the left one is the second lowest energy state for two fermionic particles in an infinite square well potential. The right one is the symmetric state corresponding to the same 1-particle states. (TimothyRias (talk) 14:56, 7 October 2008 (UTC))

That looks pretty good to me. I think it immediately communicates some of the differences in the wave functions.—RJH (talk) 17:26, 14 October 2008 (UTC)

I updated the plots with a lit more fancy formatting. Should be ready for use now.(TimothyRias (talk) 13:24, 15 October 2008 (UTC))

Thank you. So in the antisymmetric plot, when the particles switch positions the graph effectively rotates 90°? Or am I misinterpeting it?—RJH (talk) 17:08, 15 October 2008 (UTC)

Much ado about 0.1 standard deviation

Comments would be appreciated in Talk:Age of the universe#Much ado about 0.1 standard deviation. -- BenRG (talk) 22:39, 15 October 2008 (UTC)

Reducing the importance rating of various subatomic particles?

I propose reducing the importance rating given to various particles. Currently, just about every subatomic particle is given Top importance - this makes WikiProject Physics look like WikiProject Particle Physics, and also leads to lots of Top importance / Stub class articles.

How about something like the following:

Constituents of everyday matter (proton, neutron, electron, possibly also up and down quarks) - Top

The remaining quarks - High

Composite particles (Xi baryon, J/ψ meson, etc.) - Mid

I realise this might be a controversial idea, hence discussing it here before going ahead and doing it! (Apologies if this has all been discussed before - I couldn't find anything obvious.)

Djr32 (talk) 09:47, 12 October 2008 (UTC)

Well it's been somewhat discussed in Wikipedia:WikiProject Physics/Projects of the Week Wikipedia talk:WikiProject Physics/Projects of the Week, but nothing very thourough. I'll let others discuss it first, then I'll chime in.Headbomb {ταλκ – WP Physics: PotW} 13:33, 12 October 2008 (UTC)

To Djr32: You did not mention the force-carrying bosons. At least the photon, gluon, W, and Z should be top. Graviton and Higgs boson should be high. Other hypothetical particles should be mid or low. Otherwise, I agree with you. JRSpriggs (talk) 03:26, 13 October 2008 (UTC)

I tend to agree. Also agree with JRSpriggs, photon and gluon should also be top, W/Z either top or high.

To further extend this. The broader topic Quark should probably remain high, while hadron and meson should be high. We might also want to rethink the importance ratings of the various quasiparticles. They tend to be somewhat specialized concepts. Maybe phonon could qualify as top, but is probably better of as high, while the more exotic ones such as magnonshould be mid at best.

If others agree, somebody should draft a proposal for the importance guidelines. (TimothyRias (talk) 08:17, 13 October 2008 (UTC))

My proposal would be:

• Top importance: subatomic particle, elementary particle, electron, proton, neutron, quark and photon;
• High importance: all other elementary particles in the Standard Model, as well as generic terms such as fermion, boson, gauge boson, baryon, meson, hadron, lepton, quasiparticle...;
• Mid importance: most hypothetical elementary particles, as well as most composite particles and quasiparticles.
• Low importance: hypothetical composite particles; hypothetical elementary particle which are not predicted by any currently mainstream theory (e.g. preon; tachyon would fall in this classification, but I think it is a concept relevant enough for the article to have a higher importance).

Army1987 (t — c) 14:31, 18 October 2008 (UTC)

OK, well it's been a week or so and we seem to be pretty well in agreement - Headbomb, unless you disagree then I'll get started. —Preceding unsigned comment added by Djr32 (talk • contribs) 10:32, 19 October 2008 (UTC)

Have made some changes to the guidelines (actually less than I thought I'd need to - there were more things listed as being of top importance than the guidelines seemed to suggest - however, as a consequence I think I've not used every suggestion made here, even if only to keep the guidelines short) - if anyone objects then please feel free to make or suggest changes. Djr32 (talk) 19:53, 19 October 2008 (UTC)

Speed of light FAR

Speed of light has been nominated for a featured article review. Articles are typically reviewed for two weeks. Please leave your comments and help us to return the article to featured quality. If concerns are not addressed during the review period, articles are moved onto the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Remove" the article from featured status. The instructions for the review process are here. Reviewers' concerns are here. -- Testing times (talk) 14:44, 17 October 2008 (UTC)

User:Punctilius

Punctilius (talk · contribs) had made a few edits to physics articles. It now turns out that this user was a sockpuppet of Scibaby, a notorious editor who has used hundreds of sockpuppets to engage in edit warring on global warming and other climate change related articles, see here and here.

The tactic used by these sockpuppets is to first edit some articles unrelated to climate change to hide their intention. This means that these edits are often bad edits, motivated more by trying to evade detection than improving the article. So, all the edits should be regarded as highly suspect, even if they don't look bad at first sight. Count Iblis (talk) 02:41, 25 September 2008 (UTC)

It would be nice to have some type of simple ranking system that shows up in the edit history page, based on total edit history, &c.—RJH (talk) 21:05, 21 October 2008 (UTC)

Courtin_number nominated for deletion

AfD here. I've also left a notice at WikiProject fluid dynamics, but it's not clear how active that project is anymore. VG ☎ 07:05, 21 October 2008 (UTC)

Phi meson

I just created a very crude phi meson page. If some of you could expand and give a bit of history about it that would be nice.Headbomb {ταλκ – WP Physics: PotW} 16:23, 22 October 2008 (UTC)

Autoassessment for WP:PHYSICS

 Done : Approx 223 of 1583 unassessed articles checked of WP:PHYSICS were autoassessed based on other projects assessment on the same page, by TinucherianBot , per Bot request by Headbomb . FYI -- Tinu Cherian - 09:17, 23 October 2008 (UTC)

Electron PR

The Electron article has been put up for peer review here. I'm not exactly an expert, so I would greatly appreciate if somebody more knowledgeable could take a look to make sure all the facts are correct. Thank you!—RJH (talk) 17:30, 14 October 2008 (UTC)

No interest at all? You folks have this ranked as top-importance and it's on the wkipedia's vital articles list. I guess I'm just a tad surprised. Ah well.—RJH (talk) 18:05, 25 October 2008 (UTC)

Exoelectron up for deletion

AfD link. VG ☎ 08:18, 16 October 2008 (UTC)

The consensus was to keep the article.—RJH (talk) 18:03, 25 October 2008 (UTC)

Needs review

Can someone review this edit? http://en.wikipedia.org/w/index.php?title=Potential_difference&diff=247031229&oldid=245309042

Secondly, the same article's merge-tag may have also been vandalized

It has been suggested that this article or section be merged with Scalar potential. (Discuss)

but the discussion is about merging it with voltage and not scalar potential.

Lastly, can someone list some ways to improve the voltage article? The voltage article's talk page rates the article in its current state as a "C-class" article. It would be useful to know on the talk page why it has a C, especially if its partially inaccurate. Biologicithician (talk) 22:57, 25 October 2008 (UTC)

Nonsense edits by IP

The edits of 92.232.91.38 (talk · contribs · deleted contribs · filter log · WHOIS · RDNS · RBLs · http · block user · block log) appear to be all or nearly all nonsense. Could someone here please confirm? The poor grammar and idiosyncratic word choice makes it very difficult to determine if the editor actually intends to say something cogent, or if he/she is just having a nice laugh at our expense. siℓℓy rabbit (talk) 02:09, 26 October 2008 (UTC)

Cold fusion

HELP! We have Cold Fusion proponents dramatically asserting ownership over cold fusion. I need all the help I can get. ScienceApologist (talk) 15:57, 27 October 2008 (UTC)

Atmosphere of Jupiter

I submitted this article for a peer review. You can comment here. Ruslik (talk) 12:58, 28 October 2008 (UTC)

Astrophysics Data System

This is a FA article belonging to this project. Michael Kurtz, apparently an author of some of the articles used as source material, contacted me on my talk page and asked me to tag the unreferenced parts of the article. FA articles are currently being reevaluated to see if they continue to maintain FA standards. Hopefully, some editors from this project will update the page and endure that it still meets Featured article criteria. Regards, —Mattisse (Talk) 22:59, 29 October 2008 (UTC)

Project Update

• I've closed Projects of the Week since interest wasn't there.
• The "Projects of the Week" main page is now "Quality Control" as this is what was that page effectively used for anyway.
• Article Alerts (Bot-operated) is operational and will automatically report PRODs, AfD, FAC, and a lot more. See User:ArticleAlertbot and User talk:B. Wolterding/Article alerts for more details. If you notice that Article Alerts didn't report something within a day or two, please notify B. Wolterding.
• The assessment category drop down table is now a "live version" of the standard "assessement table" done by WP 1.0 bot. It is fully clickable and covers categories, redirects, images, disambig, templates, etc...
• I've put a request to have a bots tag all redirects and disambig pages as being redirects and disambig pages of NA-importance. Anomie has been kinda enough to code AnomieBOT for WP Physics and WP Astronomy.
• Quality done at 85% and importance done at 51%. We're making good progress here folks, so let's keep up the good work.

That's all for now. Feedback and comments are appreciated. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 18:46, 30 October 2008 (UTC)