Wikipedia talk:WikiProject Physics/Archive May 2013

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Domain wall - changing from disambiguation to normal page

Hello everyone! I've made recently some changes to Domain wall page. They however are not fit well to its present status. Now this page is a disambiguation page for three cases of domain wall appearances. However this is quite general object and just like page about solitons is not a disambiguation between "different meanings in particular context" it seems to me that page about domain walls shouldn't be either. I may be devoted to general features and some simple examples (phi^4!=)) The page about topological defects even already have a picture with kink=))) Of course domain walls in ferromagnetics or string theory should remain separate pages. — Preceding unsigned comment added by VeNoo (talk • contribs) 18:09, 3 May 2013 (UTC)

Domain wall was split into three articles before, to become a disambiguation page. -- 65.94.76.126 (talk) 02:15, 4 May 2013 (UTC)

Maxwell's equations: WP:LINKFARM for Further reading? History split to new article?

See this edit in good faith by user:Fgnievinski, and my reversion. Is it bad/wrong to have a further reading section like this? Books included the famed authors Landau and Lifshitz, Feynman, Griffiths, and Jackson. Thanks,

While at it, does anyone think splitting off the history section into a new article is a good plan, as proposed by Fgnievinski? I think so given the length of the article (and the history section for that matter). M∧Ŝc2ħεИτlk 22:16, 30 April 2013 (UTC)

As the sources from which most budding (English-speaking) physicists learn Maxwell's equations, it seems quite appropriate to have a list of these textbooks in the article, or a pointer to them. If the issue is list length, we could cut the list down, or put the list in its own article, similar to List of textbooks in statistical mechanics. The History and Historical publications sections are large enough for a separate article, and more importantly the topic has many reliable sources to draw from. I think it could be a successful standalone article. --Mark viking (talk) 22:48, 30 April 2013 (UTC)
I agree generally with the above and add that Maxwell's equations does seem to be an very high quality article. Xxanthippe (talk) 22:54, 30 April 2013 (UTC).
Awesome - I never came across List of textbooks in statistical mechanics before!
The list of further reading books at the end of Maxwell eqn could form it's own article in principle as more EM textbooks can be added later, and linked to from other EM articles as needed.
The history split-off has also been discussed on the talk page here by other editors. M∧Ŝc2ħεИτlk 00:14, 1 May 2013 (UTC)
I've tagged the Further reading section accordingly. Fgnievinski (talk) 05:29, 1 May 2013 (UTC)

I took the liberty of splitting off the history section to the article History of Maxwell's equations, to see how it would turn out. M∧Ŝc2ħεИτlk 07:56, 5 May 2013 (UTC)

Thanks for taking the time.Fgnievinski (talk) 07:05, 6 May 2013 (UTC)
Similarly for List of textbooks in electromagnetism. M∧Ŝc2ħεИτlk 08:53, 7 May 2013 (UTC)

Two QFT templates

Quantum field theory
Feynman diagram
History
Background
Symmetries
Tools
Equations
Standard Model
Incomplete theories
Scientists

I don't know if this has been raised before but why are there two quantum field theory templates? Should {{Quantum field theory}} be merged into {{Quantum field theories}}, since the latter is a navbox and provides all the links at one glance? M∧Ŝc2ħεИτlk 07:28, 5 May 2013 (UTC)

The sidebar ("Quantum field theory") may be more suitable for use at the top of an article while the navbox ("Quantum field theories") is more suitable at the bottom. So perhaps we should keep both. In any case, the side bar seems to have a lot more links than the navbox, so any merger should go from the navbox into the sidebar. JRSpriggs (talk) 19:49, 5 May 2013 (UTC)
Probably the reason they are separate, which I disagree since everything would be easier to follow in one place. But I'm not strongly fussed either way if they are separate or merged, just though to notify the project. M∧Ŝc2ħεИτlk 06:34, 6 May 2013 (UTC)

Vectors from the age of Lagrange and Newton

Not a long time ago, I tried (in vain) to attract attention of mathematics editors to an unhealthy situation with the title Vector (mathematics and physics). You know which various things may be denoted as “vectors” in physics, but there exist also, among others, such redirect as Vector (physics) (edit | talk | history | links | watch | logs). IMHO we should eradicate {{disambiguation}} disease in aforementioned (non-)article. Otherwise, attempts to redirect “vector (physics)” to Euclidean vector with funny arguments like because I disambiguated all article links to this redirect will persist. Incnis Mrsi (talk) 05:40, 7 May 2013 (UTC)

What is a moving crack tip temperature variation, and do physicists care about it?

Hi... you might be able to offer some insight into the questions at Wikipedia:WikiProject Articles for creation/Help desk#Review of Wikipedia talk:Articles for creation/MOVING CRACK TIP TEMPERATURE VARIATION, especially "the article doesn't state the context of this matter, nor link to anything in the context or why anyone would find this result important" ... and also the underlying question of whether this topic is notable enough to need an article, or perhaps is slightly too much original research or essay style?

Thanks! --Demiurge1000 (talk) 18:11, 7 May 2013 (UTC)

I think it's a subproblem of Fracture mechanics, as I mentioned on the help page (but that's a guess). Shawn@garbett.org (talk) —Preceding undated comment added 19:03, 7 May 2013 (UTC)

VisualEditor is coming

The WP:VisualEditor is designed to let people edit without needing to learn wikitext syntax. The articles will look (nearly) the same in the new edit "window" as when you read them (aka WYSIWYG), and changes will show up as you type them, very much like writing a document in a modern word processor. The devs currently expect to deploy the VisualEditor as the new site-wide default editing system in early July 2013.

About 2,000 editors have tried out this early test version so far, and feedback overall has been positive. Right now, the VisualEditor is available only to registered users who opt-in, and it's a bit slow and limited in features. You can do all the basic things like writing or changing sentences, creating or changing section headings, and editing simple bulleted lists. It currently can't either add or remove templates (like fact tags), ref tags, images, categories, or tables (and it will not be turned on for new users until common reference styles and citation templates are supported). These more complex features are being worked on, and the code will be updated as things are worked out. Also, right now you can only use it for articles and user pages. When it's deployed in July, the old editor will still be available and, in fact, the old edit window will be the only option for talk pages (I believe that WP:Notifications (aka Echo) is ultimately supposed to deal with talk pages).

The developers are asking editors like you to join the alpha testing for the VisualEditor. Please go to Special:Preferences#mw-prefsection-editing and tick the box at the end of the page, where it says "Enable VisualEditor (only in the main namespace and the User namespace)". Save the preferences, and then try fixing a few typos or copyediting a few articles by using the new "Edit" tab instead of the section [Edit] buttons or the old editing window (which will still be present and still work for you, but which will be renamed "Edit source"). Fix a typo or make some changes, and then click the 'save and review' button (at the top of the page). See what works and what doesn't. We really need people who will try this out on 10 or 15 pages and then leave a note Wikipedia:VisualEditor/Feedback about their experiences, especially if something mission-critical isn't working and doesn't seem to be on anyone's radar.

Also, if any of you are involved in template maintenance or documentation about how to edit pages, the VisualEditor will require some extra attention. The devs want to incorporate things like citation templates directly into the editor, which means that they need to know what information goes in which fields. Obviously, the screenshots and instructions for basic editing will need to be completely updated. The old edit window is not going away, so help pages will likely need to cover both the old and the new.

If you have questions and can't find a better place to ask them, then please feel free to leave a message on my user talk page, and perhaps together we'll be able to figure it out. WhatamIdoing (talk) 01:02, 7 May 2013 (UTC)

Correction: Talk pages are being replaced by mw:Flow, not by Notifications/Echo. This may happen even sooner than the VisualEditor. WhatamIdoing (talk) 14:33, 7 May 2013 (UTC)
This "Flow" thing sounds excessively structured. Our actual discussions do not lend themselves to such a high degree of structure. So it will fail and impede communication rather than enhancing it. JRSpriggs (talk) 03:11, 8 May 2013 (UTC)
Basically the only thing that I know about mw:Flow is that it is not mw:LiquidThreads. WhatamIdoing (talk) 01:51, 10 May 2013 (UTC)

Orphaned status of "Warm inflation"

I've tagged the article titled Warm inflation an "orphan". No other articles link to it, except a new disambiguation page. If anyone here knows of other articles from which links to that article would be appropriate, could they please attend to it? Michael Hardy (talk) 04:57, 10 May 2013 (UTC)

Fractional quantum mechanics and Fractional Schrödinger equation (again)

The previous thread will be archived soon, so let's start another one.

I added more references to Fractional Schrödinger equation, and a link to Hermann's book so we can actually see the chapter on fractional QM:

  • Richard Herrmann (2011). "9". Fractional Calculus, An Introduction for Physicists. World Scientific. ISBN 981 4340 24 3.

There is also this one:

but the link states:

"Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online."

so the last is probably not reliable, just kept it for sake of notification. M∧Ŝc2ħεИτlk 11:50, 10 May 2013 (UTC)

Thanks for hunting down and adding these references. I didn't look hard enough in GBooks. So it looks like the topic is likely notable. But it also means a good bit of work in weaning the article off the heavy reliance on, e.g., primary Laskin sources. --Mark viking (talk) 16:12, 12 May 2013 (UTC)
Yes, thanks. I'm inclined to say the topic is notable also. We can work the new refs into the article over time, and continue to look/add for more. M∧Ŝc2ħεИτlk 17:06, 12 May 2013 (UTC)

Template:Special relativity sidebar

Can some other editors please look at this navigation box and its talk page? I and another editor don't see eye to eye on whether icons should be included.--JohnBlackburnewordsdeeds 16:55, 11 May 2013 (UTC)

Incidentally, the same editor user:Thepalerider2012 on that talk page edited template:quantum mechanics today - reinstating an image I drew and temporarily added before removing it. Thepalerider2012 seems to like images in templates, other editors (including me) don't see the need for them either - we have discussed images in templates before, see here. M∧Ŝc2ħεИτlk 19:11, 11 May 2013 (UTC)

I answer here since there's several templates affected. I don't think we should have little pictures for each person in the list. The list is supposed to be navigational, and as long as you keep the images a reasonable size you can't recognize much anyway. There's also copyright issues for some, see Template:Standard model of particle physics, and it's a bit worrying that those are commentless ignored. I'm not against having a main image in each template though, that makes it recognizable and a bit infobox-like. — HHHIPPO 19:27, 11 May 2013 (UTC)

Shouldn't we try to get a consensus here whether we want icons for people in navigation boxes or not? Even if the result is 'in general yes', we have to deal with copyright problems as the ones mentioned above. Plus, the images are amplifying another problem: lists growing towards infinity as people add their favorite physicists. I don't think that a list that doesn't fit on the screen is helpful for navigation. Either way, it's affecting a number of templates, so for sake of consistency we should find consensus here. In particular, we can't override WP:ICONDECORATION without clear consensus. — HHHIPPO 17:57, 16 May 2013 (UTC)

I think we pretty much reached consensus that we didn't want pictures. I responded on the talk page of the template, but I am of the opinion that small images are unnecessary for the same reasons you mentioned. --Patrick87 (talk) 18:14, 16 May 2013 (UTC)
Agreed - we need to just remove the icons from the templates since, as it has already been said enough times before: they add nothing but extra bytes, too small to see and can bee seen just one click away anyway, increase the list length unnecessarily, and encourages people to keep adding more physicists relevant to the topic or not . M∧Ŝc2ħεИτlk 18:34, 16 May 2013 (UTC)
Note that a few days ago a similar back and forth went on at Template:General relativity, but this time by one-time user DemonThuum and anon 177.17.96.171. - DVdm (talk) 18:41, 16 May 2013 (UTC)

I've now now rolled back the remaining icons in Template:Nuclear physics, Template:Quantum field theory, Template:Quantum mechanics and Template:Standard model of particle physics. — HHHIPPO 19:49, 18 May 2013 (UTC)

Great, thank you. M∧Ŝc2ħεИτlk 20:26, 18 May 2013 (UTC)

I fixed most blatant shortcomings. But the sidebar still needs some tweaks, including changing names of sections. Incnis Mrsi (talk) 06:53, 21 May 2013 (UTC)

File:Bragg scattered light.jpg

File:Bragg scattered light.jpg has been nominated for deletion -- 65.94.76.126 (talk) 03:29, 21 May 2013 (UTC)

More eyes needed

The article on Elias Gyftopoulos seems extremely... weak in terms of explaining his notability. I added some stuff from the MIT obituary, but a lot of the content in the original version seems rather... blathery, and the references are worse. I'll accept that Gyftopoulos meets inclusion criteria, but I really can't tell what this is trying to say.

Could anyone else read the obits, and the "Gyftopoulos's collected works" site, and improve it? Thanks. DS (talk) 14:29, 21 May 2013 (UTC)

Wikipedia talk:Articles for creation/PSR J0348+0432

There's a request for help in evaluating this submission at WT:ASTRO. -- 65.94.76.126 (talk) 01:33, 7 May 2013 (UTC)

There are currently four articles which mention this pulsar including Tests of general relativity#Strong field tests: Binary pulsars where it is a red-link. Apparently, it is the best example we have now of a close binary star which is presumably emitting gravitational radiation in a strong-field regime. JRSpriggs (talk) 08:25, 7 May 2013 (UTC)
Done, I brought it into main article.Earthandmoon (talk) 08:00, 12 May 2013 (UTC)

Attribution is now broken, because of the way this article was introduced into articlespace. -- 65.94.76.126 (talk) 03:38, 21 May 2013 (UTC)

I do not see the "attribution" problem. The article appears to have been moved into main space in a way that preserves the edit history. What else could you mean? JRSpriggs (talk) 14:18, 21 May 2013 (UTC)
The history was spliced after a request was made to WP:SPLICE to fix the copy-and-paste move. The fix was done by Anthony Appleyard, which occurred after I posted this notice to WPPhysics -- 65.94.76.126 (talk) 08:59, 22 May 2013 (UTC)
Thank you for clarifying that. And thanks to Anthony Appleyard (talk · contribs) for fixing the article's history. JRSpriggs (talk) 15:02, 22 May 2013 (UTC)

(Inessential) proposal: New flow diagram of physical theories

See also: talk:quantum gravity § New flow diagram of physical theories
Where theory X lies in the hierarchy of physical theories.

Although File:Quantum gravity.png is very nicely made, how about a more complete one in SVG? This could be used in the articles suggested by the diagram other than just quantum gravity, if others approve. One unfortunate problem is the amount of whitespace in the middle and top-right corner, but it can't be helped without removing content... Feel free to criticize. Thanks, M∧Ŝc2ħεИτlk 08:21, 8 May 2013 (UTC)

Before we can even consider using this diagram, you need to be very clear about one thing — what exactly does the arrow mean? JRSpriggs (talk) 14:22, 8 May 2013 (UTC)
... also (1) what do the colours mean ? and (2) where is thermodynamics ? Gandalf61 (talk) 14:32, 8 May 2013 (UTC)
The arrows show the directions which accumulate/contain the theories. Special relativity combines classical mechanics and electromagnetism. Classical field theory contains classical EM and Newtonian gravity. Special relativity and quantum mechanics combine into relativistic quantum mechanics. Etc.
And thermodynamics can be derived from classical statistical mechanics. It's not supposed to contain every branch of physics, just the main (fundamental) ones (hence the name of the file).
For the colours: yellow is classical, blue is quantum, red is relativistic, green is special relativistic quantum physics, black is general relativistic quantum physics.
The double-headed arrows mean the theories are interrelated within one theory, i.e. classical physics is classical mechanics and classical field theory, while quantum theory is QM and QFT...
I honestly thought these things would be fairly self-evident given the labeling and would not have to explain. That's an indication for not including it, which is fine. In that case, should I just convert the original File:Quantum gravity.png to SVG for the quantum gravity article (that was the original idea)? M∧Ŝc2ħεИτlk 14:39, 8 May 2013 (UTC)
I think your double headed arrows must be removed. The concept is unclear and these are not equivalent theories. JRSpriggs (talk) 14:53, 8 May 2013 (UTC)
OK. I'll wait for more opinions before collectively making all proposed changes. Thanks for feedback. M∧Ŝc2ħεИτlk 15:32, 8 May 2013 (UTC)
Modified it, to include a bit more, removed double arrows, changed green -> purple = blue + red. M∧Ŝc2ħεИτlk 18:08, 10 May 2013 (UTC)
  • The second version of your diagram appears to be missing an arrow from "Relativistic Quantum Mechanics" to "Relativistic Quantum Field Theory".
  • It is not clear to me in what sense "Classical Field Theory" is included in "Electromagnetism" and "Classical Gravity" rather than the other way around.
  • Some items in your diagram (mostly those about statistics) appear not to have articles on Wikipedia by the name you used. Either the name should be changed or they should not appear in the diagram. JRSpriggs (talk) 05:38, 11 May 2013 (UTC)
Made suggested fixes.
However there is statistical field theory so presumably there would be a relativistic formulation called relativistic statistical field theory, but that's probably too extrapolated for now so it was removed [I can't even find much literature on this right now - there is plenty on statistical field theory (not necessarily relativistic), but none specifically on any relativistic formulations]. Additionally it's sort of strange there is no overall article on relativistic statistical mechanics: thermodynamics and kinetic theory etc can be formulated in curved spacetime (c.f. MTW), anyway removed that for now also.
Dropped the "statistical/deterministic" separation which the reader can deduce/infer by reading the articles.
The topology of the diagram is as simple as I can make it, without removing the intersecting arrow from classical field theory to QFT. M∧Ŝc2ħεИτlk 16:22, 11 May 2013 (UTC)

Oops… I missed this interesting topic for some reason. A good illustration, especially colours, but I do not agree with most arrows.

Lorentz–Einstein relativity does not depend on Galilean relativity, nor does “upgrades” it. These are different and alternative (mutually exclusive) models of the space-time. Indeed, it is easier to derive Galilean group from Poincaré group than versa. The fact that Galilean relativity appeared first is a matter of history, not one of logic.

Quantum mechanics is in some sense an “upgrade” to classical mechanics, but equations of Schrödinger and Dirac do not require anything of classical mechanics. Relation between them is not direct: it is quantization which links classical and quantum mechanics. Quantum mechanics is only partially a “mechanics”, and they also are alternative, indeed.

Field theory is not an extension of mechanics. Newtonian mechanics assumes an action at distance (including potential energy), to which the field idea is directly opposite.

Could the picture, instead of arrows, shown a kind of Euler diagram? How paradigms combine one with another to form theories. Such as:

  • Galilean relativity × particle × action at distance = classical (Newtonian) mechanics
  • Lorentz–Einstein relativity × particle × action at distance = relativistic dynamics
  • Galilean relativity × field = classical field theory
  • Galilean relativity × wave function × action at distance = (Schrödingerian) quantum mechanics
  • Lorentz–Einstein relativity × wave function(?) × action at distance = relativistic quantum mechanics
  • Lorentz–Einstein relativity × wave function × field = quantum field theory

Incnis Mrsi (talk) 16:18, 22 May 2013 (UTC)

Some comments and questions:
  • What is the times symbol supposed to mean in this context: "and" in the logic sense?
  • Why include "action at a distance" when this is just a characteristic of a theory and not a theory in itself? Same for "wavefunction"?
  • True, classical mechanics combined with EM did historically lead to SR, but conceptually this is the order they are taught and understood. The arrows above show how initially separate theories combine and they are correct... Except perhaps for the disconnected theories like classical/quantum particle mechanics and classical/quantum fields, as you say, in which case it would be better to just remove those arrows entirely.
  • An Euler/Venn diagram would introduce overlapping circles of disconnected theories, i.e. RQM as the intersection of SR and QM, then QM as a subset of QFT and SR as a subset of QFT? No matter, just need to warp the shapes, but it could look weird...
  • QFTs are not always relativistic by default, they can be non-relativistic also (considered before).
  • Above, you haven't mentioned how GR fits in, I'll try to fill that in.
I'll get the image drawn and uploaded soon... Thanks for further feedback M∧Ŝc2ħεИτlk 20:10, 23 May 2013 (UTC)
  • “×” means hybridization, you can think of it as the logical conjunction, yes.
  • “Action at a distance” is a paradigm alternative to “field”, but logically independent of other aforementioned paradigms: yes, not a standalone theory. “Wave function” – a paradigm alternative to “particle”, but logically independent of other aforementioned paradigms, including “field” (a good physicist should know that superposition of wave functions does not imply superposition of fields). Possibly, more correct names are “amplitude” or “quantum state”.
  • Possibly, something more than arrows would be appropriate?
  • (no opinion)
  • QFT – point taken, it is just wave function × field, but prepending a Lorentz group is the standard implementation.
  • General Relativity – replacement of Lorentz–Einstein relativity with the principle of gravitational relativity. Gravity itself is an alternative (the fourth in my list), not a paradigm. The principle of g.r. is its interpretation alternative to “force” (see fictitious force for explanation of this alternative is a broader context).
Incnis Mrsi (talk) 21:10, 23 May 2013 (UTC)
Main physical theories as a Venn/Euler diagram.
First, I tried to reform the previous version as an Euler diagram. Better? Anything wrong and we can take it from here. (We might take this to yours or my talk page, either is fine, to prevent cluttering this page). M∧Ŝc2ħεИτlk 23:45, 23 May 2013 (UTC)
No, “Relativity” side is fouled up. I highly appreciate your efforts, but… let us stop on your blocks layout, which consistently expresses your thoughts. In the future, I could make another diagram to express my thoughts. Incnis Mrsi (talk) 06:15, 24 May 2013 (UTC)
I have no clue why relativity is "fouled up" considering "relativistic physics" refers to SR and GR, and GR contains SR, and has the overlap with classical field theory and quantum theory for relativistic QM/QFT.
Nevertheless, enjoy creating your own anytime. Thanks, M∧Ŝc2ħεИτlk 07:53, 24 May 2013 (UTC)

Quick question to the astrophysics experts

I was just clearing up Commons category Category:Stellar evolution a little bit and were creating a new category called Category:Pre-main-sequence evolution. Now I'm not sure If I moved some files in error.

Please consider File:Stellar evolutionary tracks-en.svg as an example. Is this graph showing pre-main-sequence evolution (and is therefore correctly categorized) or does it show evolution after hydrogen fusion stops and is therefore showing the evolution of the star after leaving the main sequence? --Patrick87 (talk) 19:46, 25 May 2013 (UTC)

A Pre-main-sequence star is a star that has not yet reached the main sequence. The file you mentioned shows the main sequence and post-main-sequence evolution for a number of different star types. Evolution after hydrogen fusion stops is I believe considered post-main-sequence. So I would say that this illustration is not about pre-main-sequence evolution. --Mark viking (talk) 20:16, 25 May 2013 (UTC)
Yes, I know what a PMS star is. What I don't know is how to tell whether the image shows pre- or post-main-sequence evolution since they look very similar. There is a very similar image to the first one at File:Hayashi track it.svg that clearly shows pre-main-sequence evolution. Probably I only got confused because I found it first. But I want to be sure the image in question really shows post-main-sequence evolution. --Patrick87 (talk) 21:56, 25 May 2013 (UTC)
These tracks are definitely post-main-sequence, not pre-main-sequence. --Amble (talk) 01:02, 26 May 2013 (UTC)

Conduct of IP 84.20.238.83

The IP 84.20.238.83[1] has been repeatedly placing references to un-notable papers on several important physics articles.[2] He even added one to the article on Paul Dirac. He continues to do this after several warnings on his talk page. I sugggest that a block may be needed here. Xxanthippe (talk) 00:42, 31 May 2013 (UTC).

Physics for People Who Hate Physics

Unfortunately, many of our articles are written this way:

"The simple approach to physics is too dogmatic, & the people who advocate it are theorists, not real physicists, and should not be allowed to teach theory courses like this one. (Dogmatism is reserved for the accompanying lab course.) Beginning with a simple, general understanding is too formal: A real physicist works through all the examples, & then tries to understand it later; hindsight is more educational than foresight. It is only by repeating all the same mistakes that physicists made historically that one can learn history (although the student may need to repeat this physics course). This method was good enough for all physicists so far (except the formalists of the 1960's & 1970's), so it's good enough for the future. To follow history one must teach things the way they were first learned -- as a confusing mess. By this method physics can be shown to be as manly as any other subject, & its intrinsic simplicity & beauty can be buried at the end of each topic, by which time it will not be noticed."

Count Iblis (talk) 23:28, 31 May 2013 (UTC)

I agree wholeheartedly with this sentiment. We have a lot of articles on topics which could be quite interesting, but for the fact it's a long list of derivations in some obscure notation, with little mention of what the effect means physically or is good for. We have our work cut out for us... a13ean (talk) 23:35, 31 May 2013 (UTC)
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