Wikipedia talk:WikiProject Physics/Archive February 2013

Student projects

Following the message posted by Andrew Gray back in November, I just want to let everyone know that two University of Glasgow students are working on expanding a couple of articles: Curie temperature and SASER. If anyone has suggestions on how to improve these articles, please let them know. --Nicalacla (talk) 08:56, 1 February 2013 (UTC)

template:Classical physics

{{Classical physics}} has been nominated for deletion -- 65.92.180.137 (talk) 01:05, 3 February 2013 (UTC)

I stated that in the top section. M∧Ŝc²ħεИ_τlk 07:59, 3 February 2013 (UTC)

WP:PHYS does not have its Manual of Style yet

I just went from cleansing an incredible amount of “<math>e^-\,</math>”, “<math>U(1)</math> we use here”, and “emission of a <math>W^-</math> boson” in the Standard Model (mathematical formulation) article. But I even am not sure that abominations will not be reinstated, because no guideline says that one should refer to a weak force carrier as “
W⁻
”, not “$W^{-}\,$”. Incnis Mrsi (talk) 21:57, 2 February 2013 (UTC)

I occasionally do the same conversion where "<math>" is silly. Good of you to point out no page for Wikipedia:Manual of Style/Physics (in short WP:MOSPHYS or whatever) also, should we create it? M∧Ŝc²ħεИ_τlk 22:16, 2 February 2013 (UTC)

Before anyone raises it - yes there may be overlap with WP:MOSMATH, but that page doesn't (or at least shouldn't) cover physics conventions. M∧Ŝc²ħεИ_τlk 22:23, 2 February 2013 (UTC)

The easiest way to prevent overlap is not to cover overlapping topics. Physics-specific notation or other style should be left to any sort of physics MOS. --Izno (talk) 23:56, 2 February 2013 (UTC)

Yes, that's what we're trying to infer. Let's see how much consensus there will be (hopefully without the thread simply stalling). M∧Ŝc²ħεИ_τlk 08:08, 3 February 2013 (UTC)

Or better still, add some shortcuts to sections within WP:MOSMATH and cross-reference those shortcuts. Martinvl (talk) 09:49, 3 February 2013 (UTC)

I saved a draft at Wikipedia:MOSPHYS. Feel free to edit it. Incnis Mrsi (talk) 11:44, 3 February 2013 (UTC)

Looks good! Thank you, M∧Ŝc²ħεИ_τlk 12:08, 3 February 2013 (UTC)

Nice start. -Dilaton (talk) 20:20, 3 February 2013 (UTC)

A good start, but one comment - you recommend denoting dimensions by enclosing the symbol in square brackets thus "[M]". I notice that the International vocabulary of metrology - Basic and general concepts and associated terms (VIM) does not use square brackets, but upright uppercase letters. Do you have a reference where square brackets are used?

I also noticed that in one of the early sections, you had three columns. If you narrow the page down, they run into each other. Maybe you should think of re-formatting that part of the page.

Martinvl (talk) 22:24, 3 February 2013 (UTC)

Well I have seen books and people use them before, please don't ask me for refs right now... I'll tweak the square brakets bit. M∧Ŝc²ħεИ_τlk 23:00, 3 February 2013 (UTC)

Some notes on the draft:

• Why do you often (but not always) use {{bigmath}}? I looks out of scale in my opinion. Mixed up with standard size {{math}} it just looks irregular.
• Is it really fortunate to use {{math}} templates at all? I think they are rather hard to read and make the code more complex than it would be with default TeX syntax in <math> tags. Futhermore I had the impression most editors used TeX syntax anyway?
• I'd put the "recommended" columns in front of the "not recommended" columns. Maybe even use "deprecated" instead of "not recommended"?

-- Patrick87 (talk) 00:49, 4 February 2013 (UTC)

What means "out of scale"? Presentations in the MoS draft demonstrate, first of all, which notation to use (to avoid bars and bold-italics for vectors, italicized substances names, etc.), and concrete samples are not posed to be ready-to-include into articles. And please, don't stray into the "<math> vs {{math}} vs HTML" flamewar here. Feel free to discuss and/or edit WP:«math» for that purpose. Incnis Mrsi (talk) 09:31, 4 February 2013 (UTC)

"Out of scale" means "to big" in this case. I don't like it when the text in formulas appears larger than the surrounding text. I'd accept the argument that we want to show the formulas larger than normal to point out the important details but then all formulas should use {{bigmath}} for consistency.
I'm sorry if "<math> vs {{math}} vs HTML" is a soft spot here; I wasn't aware of that and since I personally felt that TeX syntax was predominant I just wanted to give a short pointer into that direction. -- Patrick87 (talk) 10:30, 4 February 2013 (UTC)

Help from project members requested

There is an ongoing (larger) debate over sources used for/at the Clockwork universe theory. The ongoing debate is at Wikipedia:No original research/Noticeboard#Clockwork universe theory and is not progressing because of lack of outside opinions on the matter.Moxy (talk) 22:10, 5 February 2013 (UTC)

I thought I got a pass on having to deal with this sort of thing by being an experimentalist... Will comment shortly. On second thought, I'm going to have to pass after all, sorry. a13ean (talk) 22:34, 5 February 2013 (UTC)

Power surge

Currently, Power surge is a disambiguation page; however, it seems to me that the clear primary topic of the term is a "surge" in "power". This page was previously a redirect to voltage spike, and I am wondering if there is any real difference between a power surge and a voltage spike. Cheers! bd2412 T 14:04, 6 February 2013 (UTC)

My understanding is that there is a difference - from a physics point of view, a voltage spike is destructive because damage is caused by a high voltage potential - typically exciting electrons into higher states due to the high voltage potential and thereby changing the electrical characteristics, resulting in a power surge down the new low resistance path, (as in a lightning strike) whereas a power surge is destructuve because of ohmic overheating (as in increasing the voltage to an electrical appliance). Martinvl (talk) 14:16, 6 February 2013 (UTC)

I agree about the difference. On the other hand Voltage spike seems to aim at covering not only actual voltage spikes, but also spikes of current and energy. The article claims there's also a difference between spikes and surges, but that is unsourced and contradicted by Surge protector. So I guess a redirect from Power surge would be OK. Btw the article needs quite some work to make it more coherent. — HHHIPPO 20:59, 6 February 2013 (UTC)

Bose–Einstein statistics

“ Quantum effects appear if the concentration of particles satisfies,

${\frac {N}{V}}\geq n_{q}$

where N is the number of particles and V is the volume and n_q is the quantum concentration, for which the interparticle distance is equal to the thermal de Broglie wavelength, so that the wavefunctions of the particles are touching but not overlapping.

”

I’m not an expert in quantum statistics and am not willing to fix the touching-but-not-overlapping rubbish with the risk of injecting my own crap. A volunteer? Incnis Mrsi (talk) 20:06, 5 February 2013 (UTC)

Removed it but would prefer if someone could think of something that still captures the essence of what touching but not overlapping is trying to say. AHusain (talk) 06:05, 7 February 2013 (UTC)

Thanks for the attempt, but [1] replaced the rubbish with a crap. Unless the state is non-entangled, such thing as the wave function of a distinct particle in a multi-particle system does not exist at all; see Wave function #Definition (other cases) for details. If particles interact, then the state of such system is almost certainly entangled. Incnis Mrsi (talk) 12:24, 7 February 2013 (UTC)

Please help with the topic "the limits of an optical telescope"

Please, if you would, read this Talk:Optical_telescope#How_big_can_they_get.3F thread and respond as you would. Thank you! Chrisrus (talk) 16:06, 10 February 2013 (UTC)

Entropy

Do we have too many articles on Entropy?

An anon who's recently done quite a lot of re-writing at the Entropy article is suggesting that Entropy (classical thermodynamics) be merged to it.

Do people think this is a good idea? Discussion at Talk:Entropy#Merger_proposal Jheald (talk) 12:51, 12 February 2013 (UTC)

Vickers hardness

The chemical elements pages contain a point Vickers hardness and Brinell hardness and there it is given in MPa which was pointed out at Talk:Tungsten#FA nomination is strange. The definition of both test does not include the MPa but that it is a force divided by an area.

Please answer at the Wikipedia talk:WikiProject Elements#Vickers hardness --Stone (talk) 22:37, 12 February 2013 (UTC)

Compressed air energy storage expert help?

Could an expert please take a look at this from Talk:Compressed air energy storage#LightSail.com claims 70% round trip power efficiency using water mist cooling?

Please see http://www.lightsail.com/tech.html and their CEO's Google Solve for X talk from a few days ago for the details, but I'm not sure which category (e.g. hybrid etc.) this fits into. so could someone please add it to the article? Apparently using water mist as a heat exchanger is a completely new idea bringing efficiency from 30% to 70%, and LightSail has patents on it. I'd feel more comfortable if an expert took a look at it before it was added.

Thanks. Neo Poz (talk) 23:17, 12 February 2013 (UTC)

Please take a look

I would like some people to take a look at this new article - Ernest Bohr. There is a claim of family members working on the Manhattan Project, but there are no sources that back up this claim. Also, sources do not generally support the notability of this person. And, so far I am not seeing reliable sources. So, I tagged it for "Notability" for this person in general, and "Dubious" for the claim about the Manhattan Project. I also commented on the talk page. Thanks ---- Steve Quinn (talk) 18:44, 12 February 2013 (UTC)

The sentence was: Niels and Ernest's older brother Aage Bohr travelled to the United Kingdom in October 1943, and thence to the United States, where they participated in the Manhattan Project. There is nothing controversial about that. Aage won the Nobel Prize for Physics (shaped of the atomic nucleus) in 1975. I removed the sentence anyway because it is not essential. I would guess that the intent of the author was to account for the fact that the family was split up during that time.--180.183.41.215 (talk) 21:32, 12 February 2013 (UTC)

OK thanks for clearing up this matter. I didn't realize that Aage Bohr won the Nobel Prize for discoveries pertaining to the atom, and I couldn't figure who "they" were that worked on the Manahattan project. Without researching this myself it is still vague. Anyway, I agree that the sentence is irrelevant to the article, and removing it is appropriate. Thanks. ---- Steve Quinn (talk) 15:31, 13 February 2013 (UTC)

Minor conflict in Vapor–liquid_equilibrium

talk: Vapor–liquid equilibrium #The HTML equations were badly rendered with a number of errors

Of course, I can do something wrongly. But if my revision was accused in “a number of errors”, then I expect from an opponent, on my request, to point to at least two errors explicitly, not to dodge on various pretexts the discussion about concrete problems. In any case, mbeychok’s diff does not contain any formula which was altered in a way which shed some light to a former “error”. Incnis Mrsi (talk) 10:49, 14 February 2013 (UTC)

Inquiry about symbols and formulas on Physics related articles

Dear WikiProject members,

I've encountered a few articles with unexplained and "hard to search for" symbols in formulas. For example here d-Omega-squared, and here G_F and G_N (also "size of a dimension" isn't wikified, and Compactification (physics) is also not much of a help). I've no problems with formulas, after all, physics is about models and their predictions, and that means math and laborious letter-crunching, but without a dictionary even the mathematically brave can't successfully begin to understand much.

So, I'm interested in your stance on these issues. In case, this is already an over-discussed problem, please point me to the relevant archives. Thanks, PAStheLoD (talk) —Preceding undated comment added 17:17, 16 February 2013 (UTC)

Nice irony. It's not over-discussed, but it is currently discussed. Why not to join? Incnis Mrsi (talk) 17:23, 16 February 2013 (UTC)

Thanks for the quick response. No pun (or in this case, irony) was intended. (I searched this talk page and the January archive for "symbol" and "formula", and haven't found anything relating to my question.) Not that I think typesetting is unimportant, but it might be, at least, less relevant how something looks if none of the possible visual presentation versions confer any more meaning to the reader. Of course, if a MoS is supposed to cover more than that, then great, I'm hoping it'll have sections covering accessibility of concepts, symbols, formulas and models for folks the less versed in a given (sub)field. Pas (talk) 18:37, 16 February 2013 (UTC)

Indeed, WP:MOSPHYS is intended to cover also which kind of prior knowledge should be expected from the reader. Input from a non-physics expert might be quite useful there. Regarding your specific examples:

• r²dΩ² here stands for r²(dθ² + sin²θ dφ²), the angular part of the line element for the Schwarzschild metric. Maybe the notation should be introduced there, since dΩ is also used for solid angles, which is not the same.
• G_F and G_N seem to stand for the coupling constants of the weak force and of gravity. I think here the whole paragraph, if not the whole article could use some improvement.
• For the size of a dimension, there's a useful description in the 3rd paragraph of Kaluza–Klein theory. I agree that's hard to find, and there are several articles where a definition should be given or at least linked.

I'm afraid I don't have the time and the expertise to fix it all, but coming back to your original question: yes, all these articles need improvement. It's not that they're hard to understand because we want it that way, they're just not done. Asking on the respective talk pages, or here, might yield someone who'll do it. — HHHIPPO 13:26, 17 February 2013 (UTC)

G_F appears at Fermi's interaction#Fermi constant. JRSpriggs (talk) 02:58, 18 February 2013 (UTC)

Realism

The usage of realism is up for discussion, see Talk:Philosophical realism -- 65.92.180.137 (talk) 00:08, 21 February 2013 (UTC)

Interpretations of quantum mechanics

Does this qualify as WP:BOOKSPAM? — HHHIPPO 20:48, 21 February 2013 (UTC)

I think that this, as well as that, are a WP: Conflict of interest. Of course, yet one or two such edits and those would qualify as a spam, too. Incnis Mrsi (talk) 19:14, 22 February 2013 (UTC)

I suggest remove them unless secondary sources show that they are important enough to find a place in the article. Xxanthippe (talk) 09:37, 25 February 2013 (UTC).

 Done — HHHIPPO 22:13, 25 February 2013 (UTC)

Well, this was, of course, a case of WP: Conflict of interest; I'm sorry about that. I think my book would be an interesting reference in this context, but I'm not the right person to decide on that. So if any of you would like to make up his mind and have a closer look at the primary source... please feel free to do so :-) Sébastien Fauvel (talk) 00:39, 26 February 2013 (UTC)

Form/structure/application of Template:Tensors

Not an burning issue, but input/feedback may be helpful at Template talk:Tensors if time/inclination allows. Thanks, M∧Ŝc²ħεИ_τlk 09:33, 25 February 2013 (UTC)

The same topic has been raised on a number of navbox talk pages. I think it's better to discuss it here, since it seems to be a move aiming at abandoning navboxes in general. There's different opinions about the various navigation systems all over Wikipedia, and probably the same here. I personally think navboxes generally do more good than harm and at least most of them should be kept. — HHHIPPO 21:10, 25 February 2013 (UTC)

True, many of them are useful, those which are pointless can be or have been deleted (see for example template:Physics equations, Template:Physics equations (eponyms), also the recently deleted template:classical physics, as you know of course). A lot of people do favour the boxes, because they have been added to the articles, but some argue they are "grab-bags" of links (which sometimes is the case).

As a rule of thumb;

• if they do serve to navigate between related articles of broad subjects, they should be kept as they collect familiar and unfamiliar topics and allow quick reading between them,
• if they simply stuff lists of links only for the sake of having "portable lists" (as the mentioned deleted templates did), then they are not acceptable because they contribute to template creep and that's where categories and "list of... articles" can be useful.

Obviously we can't please everyone all of the time... M∧Ŝc²ħεИ_τlk 08:35, 26 February 2013 (UTC)

Update: I created a navbox version there, since some editors think that's the better form. M∧Ŝc²ħεИ_τlk 09:19, 26 February 2013 (UTC)

I'm going to change {{tensor}} to the navbox version - due to consensus and no objections for that. M∧Ŝc²ħεИ_τlk 21:14, 26 February 2013 (UTC)

I wonder if it would be more practical to use a different name for the footer style version, since that also goes to a different position in all the articles. Once there is no transclusion of the sidebar style version left, and still no objections, one can redirect that to the new version. — HHHIPPO 21:27, 26 February 2013 (UTC)

Heh... Just started to go through the articles using that template and move them to the bottom... I don't think anyone will ever create consensus to use the sidebar version... Sorry! M∧Ŝc²ħεИ_τlk 21:33, 26 February 2013 (UTC)

No problem. Have fun ;-) — HHHIPPO 21:50, 26 February 2013 (UTC)

Picture proposal for template:classical mechanics

Yes - I'm sorry to annoy people with the template:classical mechanics again!... Again, it's a completely inessential issue, but having created the image for the quantum mechanics template, I created a picture for the classical mech template. It will affect all those articles, so if time/inclination allows please feel free to favour/oppose the picture for the template. Many thanks, M∧Ŝc²ħεИ_τlk 10:22, 26 February 2013 (UTC)

I would like to record that I dislike subject-area templates at the top of articles, and images in such subject-area templates even more so. My reason is that boxes with images at the top of articles on WP most commonly signify infoboxes -- i.e. information and images that directly correspond to the topic of the article itself. Placing an image in this spot that does not relate directly to the article at hand is a practice I think can be highly confusing, and not at all to be encouraged. Jheald (talk) 11:02, 26 February 2013 (UTC)

Very well. Other editors think that sidebars should become navboxes or just be deleted also, and I partly agree (cf above and links therein). The pictures in templates are to summarize the subject in the same way people add a picture at the top of an article... Thanks for feedback... M∧Ŝc²ħεИ_τlk 11:16, 26 February 2013 (UTC)

Sorry. I didb't mean to be bitey, and I do think that navboxes can be very useful indeed, so I do appreciate what you're doing. But I do have concerns about how some of these sidebars sometimes come over. The {{Thermodynamics}} template, for example, makes me wonder every time whether that diagram is supposed to be being directly relevant to something in the article at hand -- and if so, what. Jheald (talk) 11:51, 26 February 2013 (UTC)

You make a good point and it's not bitey. Solution to the problem of a picture at the top right corner include:

• converting all sidebars to navboxes (which people will naturally oppose), leaving room for the picture,
• moving the leading relevant picture for the article in the center of the lead, and placing the sidebar to the side, like in tensor (currently that template is discussed also)...

Best, M∧Ŝc²ħεИ_τlk 12:22, 26 February 2013 (UTC)

I agree that templates with tons of links are better off as footers than as sidebars (e.g. {{tensors}}). I also agree that an image directly corresponding to the specific topic of an article should have priority for putting in the top right corner (like in Tensor: the image in the center creates huge amounts of whitespace, and the TOC again shortly after. Both could be avoided by having the image floating in the top-right corner and the sidebar below). But there are also many pages on abstract topics where it's hard to find an image that's clearly associated with the article (e.g. in the area of string theory). For those, I like the fact that the sight of a familiar 'icon' (or if it's not familiar, at least a clear header) immediately tells me about the field of the article, or in which corner of Wikipedia I am. I would even support the idea of using such templates on minor articles from that field, which are not themselves listed in the template.

But then, looking through our articles with and without sidebars, there's good and bad examples for both, and a lot of inconsistency. I guess it ultimately has to be a decision at each article what kind of template to use, even though some general guidelines would be nice. If we can ever come up with some consensus... — HHHIPPO 20:18, 26 February 2013 (UTC)

To be honest, the substance of your argument could be in WP:MOSPHYS (guidelines on sidebars/navboxes are not even mentioned). As you say, all we need is consensus from the rest of the project. Thanks, M∧Ŝc²ħεИ_τlk 20:27, 26 February 2013 (UTC)

Hope you don't mind me using your previous post to write a section on this matter. Maybe that will speed up gain of consensus, given that these are the physics article guidelines... M∧Ŝc²ħεИ_τlk 20:45, 26 February 2013 (UTC)

I don't mind, good idea. Will probably need some tweaks and discussion, but it's a good start. — HHHIPPO 21:21, 26 February 2013 (UTC)

Hastatic order?

I'm not sure if this should go here or in WikiProject Chemistry, since it involves a uranium compound, thus chemistry, but also has to deal with time-reversal, which would be physics. So, not sure where I should be asking this question, but whatever, i'm here now.

I'm thinking we should really have an article on Hastatic order, which is a new concept or...property of matter, I suppose, that was just properly described in January (though first seen around 30 years ago). You can read the original Nature article on it here. There's plenty of news articles on it, see here, here, and here. And more scientific places, see here as one example.

So I think this should have an article, but I am sadly not smart enough to understand how quadruple time-reversal symmetry works, so I don't feel comfortable attempting to make an article on the subject. Anyone up for the challenge? Silverseren^C 01:20, 25 February 2013 (UTC)

Anyone? Silverseren^C 02:29, 28 February 2013 (UTC)

News reports are not really reliable sources are they? The one you found in nature does include an article reference though, which is a better start than nothing. We should look for peer-reviewed papers and books (textbooks/research monographs) on the subject. M∧Ŝc²ħεИ_τlk 07:52, 28 February 2013 (UTC)

While they are certainly not as high level as peer-reviewed papers, news reports are still perfectly fine reliable sources. But as for other papers, there looks to be a few usable things here. We might need to wait for some more stuff to be created in the future in order to make a sufficiently in-depth article, but a stub shouldn't be that difficult with the sources available right now. Nature also published this news report that goes into quite a bit more depth on the physics of the subject than the more general news articles I linked before do. Would this count as a review, actually, since it was published as part of an issue of Nature itself? Silverseren^C 10:52, 28 February 2013 (UTC)

Nature is a peer-reviewed journal (see here). A quick look on Google gives this paper from arxiv.org. Create the stub if you want, but it's not an essential article. Maybe it's better to wait a while for more papers. You may get more answers/experts from WikiProject Chemistry (as you originally stated) than here given that it's a chemical compound (although members here with expertise in condensed matter physics would be helpful). Thanks, M∧Ŝc²ħεИ_τlk 14:05, 28 February 2013 (UTC)

Agreement on notations/conventions for physics articles

To those it may concern... (really this is aimed at all serious members of this project, but understandably not everyone can or will reply)...

Please see here, where we need to all agree on some (open?) questions on typesetting within physics articles. Some of it may seem trivial and you may just refer to WP:MOSMATH, but that can't be the only resort. No intension to dominate the new MoS, which is why I'm asking. Thank you, M∧Ŝc²ħεИ_τlk 20:49, 27 February 2013 (UTC)