Talk:Field equation

Text and/or other creative content from Field equation was copied or moved into Classical field theory with this edit. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists.

Early thread[edit]

I created this article some time ago (the anon was me) and realise that it needs a huge cleanup. Amongst many other things, perhaps examples of field equations from important theories should be included. MP (talk) 12:33, 3 January 2006 (UTC)[reply]

More cleanup ideas[edit]

Some ideas to give the article more substance:

Need a discussion of Poisson's equation for gravitation.

Mention something about Lagrangians (and conservation laws).

Describe the field equations for each theory in a little detail (mathematics used, analogies with other field equations, generalisations to other theories (e.g. n-dimensional Einstein field equations).

Field equations for theories of gravitation other than GR (emphasise similarities and differences).

MP (talk) 11:11, 4 January 2006 (UTC)[reply]

I've gone some way in addressing these issues you've raised; the level of detail this article deserves is something I'm still considering.

--Masud 05:20, 28 September 2006 (UTC)[reply]

Does Poisson derivation belong here?[edit]

Having just spruced up the first 2 subsections, I'm now not entirely sure that the outline derivation of Poisson belongs here. I put it there because I wanted to show how it came about from just considering force fields (as we had done above) with the additional machinery of potentials.

Re-started[edit]

IP 75.139.254.117 has re-started the article. It was agreed on here to merge the content of this article (field equation) into classical field theory.

Does anyone agree with the current version of the article? It does not read clearly. Do we actually need this article at all? Even when expanded, it will overlap a number of extra articles like relativistic wave equation, equation of motion, quantum field theory itself... I think it is superfluous but open to suggestions. M ∧Ŝ c²ħε И_τlk 11:27, 20 December 2016 (UTC)[reply]

So far it is more like a disambiguation page than an article. It might be a good idea to have a disambiguation page; we didn't even provide a hatnote at the top of Classical field theory for anyone interested in quantum field theory. The question would then be whether to keep Classical field theory as the primary topic; based on our previous discussion I would favor that. RockMagnetist(talk) 18:03, 20 December 2016 (UTC)[reply]

My reason for restarting was that I'm tired of this article not existing. I hadn't realized it existed previously. It is an obvious landing page, and is not as helpful as it could be by redirecting to classical field theory, to the exclusion of many other varieties, such as qauntum, string, and assorted others. As I've stated elsewhere, I'm not happy with how difficult it is to piece together information from those assorted articles to get an understanding of a basic topic, and many of the assorted articles are overly broad as it is, and could benefit from partial delegation to this article. I'm ok with this being a disambig page, but it's nature should be of the dabconcept variety, which in principle should include at least a light overview of the concept. I feel it could easily grow from that into a full article, and don't really see much downside of having the article exist. 75.139.254.117 (talk) 02:12, 21 December 2016 (UTC)[reply]

I'd favour this page as a disambiguation page also, and keeping classical field theory as the primary topic, since an understanding of QFT requires an understanding of classical FT anyway.

If this page is to be an article, it would likely split into sections on classical and quantum field theory, resulting in overlap/duplication elsewhere. It could be a list of all the main field equations with background (about the field equations, not the full theories of CFT and QFT entirely). M ∧Ŝ c²ħε И_τlk 09:19, 21 December 2016 (UTC)[reply]

In reply to the comment by 75.139.254.117, one reason that I favor a disambiguation page is that I'm not sure the various field equations have much in common. But I could be persuaded otherwise if you can find a general source that discusses them in a unified way. RockMagnetist(talk) 16:17, 21 December 2016 (UTC)[reply]

They have all kinds of attributes that can usefully classify them to a novice independent of classical/quantum. Some examples: relativistic/non-relativistic, massless/massive, charged/neutral, scalar/vector/tensor, linear/non-linear, spinor/twistor, etc. This is exactly why I felt the article was missing. The assumption that you have to go through classical field theory as a first step is not true, especially if you are trying to get a 50,000 foot view. A classification-oriented approach is more approachable in this regard. — Preceding unsigned comment added by 75.139.254.117 (talk) 07:52, 24 December 2016 (UTC)[reply]

I will also say that I don't agree with the force-feeding of classical theory to every reader of this article. If the reader cares about classical theory, they can read that article, but assuming the reader *must* do that is making unwarranted (and frankly, annoying) assumptions. It is a way of talking down to the novice readers, who may want to learn more without taking an entire course of force-fed dependencies. — Preceding unsigned comment added by 75.139.254.117 (talk) 08:08, 24 December 2016 (UTC)[reply]

You can write the article if you want to. But no-one is "force-feeding" classical field theory into anyone. CFT is the primary topic, for all the classifications you listed, even overlapping with QFT equations. M ∧Ŝ c²ħε И_τlk 11:17, 24 December 2016 (UTC)[reply]

75.139.254.117, you make a reasonable case for creating this article. But if you are going to carry on, please add some sources before you add any more text. Remember that Wikipedia is all about verifiability. RockMagnetist(talk) 16:32, 24 December 2016 (UTC)[reply]

Many, dare I say most, of the articles on Wikipedia were created prior to being properly sourced. Telling me to source my edits is yet another way of talking down to novices. While Wikipedia is an encyclopedia, and deserves to be properly sourced, making it a requirement to source up front is not a necessity, and is actually something that is better suited to the experts, not the novices. I suspect the real concern here is that I've said things that were factually inaccurate. If that's the case, the proper response for someone knowledgeable is to fix the factual errors, and source them, if possible, not to deny access. Food for thought. I'm not making the assumption that this is "my page" to write. I welcome anyone who is interested to contribute. — Preceding unsigned comment added by 75.139.254.117 (talk) 18:17, 24 December 2016 (UTC)[reply]

Many new articles have also been deleted or tagged for {{notability}}, and there's a high correlation with lack of sources. I often have to clean up articles that are loaded with dubious, unsourced material; and it's more work for me to find the source for someone else's material than to scrub it and start over with my own sources. If you're not willing to make the effort to find sources, than maybe we should revisit the idea of a disambiguation page. RockMagnetist(talk) 20:37, 24 December 2016 (UTC)[reply]

This is not "talking down to novices." It's a reasonable expectation, and adding sources is not hard. My very first edit of an article involved adding a source. I have almost never added unsourced material, and as a result my contributions to articles tend to be permanent. People who don't source their material waste a lot of time arguing about it on talk pages. RockMagnetist(talk) 20:45, 24 December 2016 (UTC)[reply]

You are entitled to your own opinion, but I don't feel it's reasonable to expect novice volunteers to source articles. I really don't care about your first edit, or what you feel is easy/hard. This isn't really about you, so I don't know why you have made it about you. But if you want my help, you'll be respectful of my good faith efforts. — Preceding unsigned comment added by 75.139.254.117 (talk) 21:05, 24 December 2016 (UTC)[reply]

I think you will find that others in Wikipedia share my view of what is reasonable. I will give you the benefit of the doubt for now, but if this article is still unsourced in a couple of weeks I'll be revisiting the idea of turning it into a disambiguation page. Bye for now. RockMagnetist(talk) 21:10, 24 December 2016 (UTC)[reply]

Yes, there are other Wikipedians that make those same unfounded assumptions. So what? Unfounded is unfounded. Speaking of unfounded, why do you assume I'm writing a complete article? Nothing I've said suggests that, and in fact I've already stated I'm ok with this being a disambiguation page, but I feel the appropriate type is the dabconcept type.

Your suggestion that field equation is not a notable topic is also ludicrous, as any Google search will show; suggesting you will remove my efforts is just a bullying tactic. — Preceding unsigned comment added by 75.139.254.117 (talk)

You seem to want it both ways; you're playing the novice card to avoid putting effort into this page while using jargon like dabconcept and lecturing me (an admin) on how things should be done on Wikipedia. My "unfounded" opinions are based on years of experience. I'm fine with this being a dabconcept page, but have a look at the examples in WP:dabconcept. Do they have sources? RockMagnetist(talk) 00:24, 26 December 2016 (UTC)[reply]

I am a novice to physics; I'm not an expert. If that's "playing the novice card", then so be it. I'll bet a lot of the novices are browbeaten into not sticking up for themselves. I'm not, however. Wikipedia, however, is a different area entirely--I'm not an expert there, either, however. I was around in the early years when administrators were more tolerant, and believed in the core principles. The core principles have nothing to do with who does what work. I offer to you that I enjoy contributing to Wikipedia, and I wouldn't if it felt like work. What you are telling me in return is that I should accept an arbitrary set of principles that were never part of that core ideaology, and which sound an awful lot like they aren't very enjoyable. I don't accept that, and since this is a volunteer organization, I don't see a problem with that. If however, you feel like it makes more work for you, then I suggest you examine why you feel that way. As I've said, it's a volunteer organization. You don't have to do anything you don't feel like. Trying to make me the target of your misplaced feeling of obligation is irrational. I didn't feel I was lecturing you, either, to be honest; not sure why you felt that way. I certainly was trying to get across that I wasn't ignorant. That's because I felt that I kept being talked down to, as I expressed repeatedly (and seemed to continue to get condescending responses). I do want to say that I've had other experiences on Wikipedia that were much worse and actually caused me to leave for a while. Having admins that are receptive enough (like I experienced here) to talk through the issues is a big help.

I'm actually pretty happy with the direction the article has now taken. The article now has a solid foundation, an can continue to evolve. That's certainly the direction I wanted, and was not something I could have done on my own. My biggest disappointment was that this didn't happen automatically, as it would have in the early years, but instead required this whole discussion. 75.139.254.117 (talk) 01:57, 28 December 2016‎

I have attempted to shape the article into what people may be looking for, with a few refs which cover classical/quantum field theory, page numbers will be added. If a DAB page is preferred it can be trimmed or just reverted. M ∧Ŝ c²ħε И_τlk 11:23, 26 December 2016 (UTC)[reply]

That's looking good! Thanks, Maschen. I should have been following my own advice and doing something like that instead of trying to get someone else to do it. RockMagnetist(talk) 16:58, 26 December 2016 (UTC)[reply]

Thanks for the kind feedback, it should be the IP if anyone making the effort. M ∧Ŝ c²ħε И_τlk 09:20, 27 December 2016 (UTC)[reply]

My recollection of events was that I started this article (apparently re-started it), in a good faith effort to improve the article. I'm not sure how that amounts to not making the effort, but you are entitled to your opinion. — Preceding unsigned comment added by 75.139.254.117 (talk) 03:48, 28 December 2016 (UTC)[reply]

You just about restarted it, without sources. FWIW - I am not an expert in physics/maths either. M ∧Ŝ c²ħε И_τlk 11:33, 28 December 2016 (UTC)[reply]

Your own words said I restarted it without using a sourcing qualification to begin with. Apparently you've changed your mind about what that means in the interim. But I don't really want to debate that point. For my part, I don't have any prescribed notion of "re-start". I am a little concerned about the expectation for volunteers to source articles. That seems to be Wikipedia sowing the seeds of it's own demise. Let me explain.

Currently, there are two groups of participants in Wikipedia, anonymous editors like myself, and administrators. Wikipedia seems to be moving in the direction of eliminating this distinction on a number of fronts. They are certainly encouraging anon editors to become admins, and I see no problem with that. But where I see a recurring problem is with setting expectations for anon editors that match current expectations for admins. I'm not sure I see the logic in that. Where does that lead? It certainly alienates the anon editors that were contributing without wanting to be obligated to admin duties. I don't think that's a small group. But that's the way WP continues to come across to me in the actions of the admins. YOU MUST BECOME AN ADMIN OR ELSE YOU ARE A SECOND-CLASS CITIZEN, AND WE WILL TREAT YOU AS SUCH. That is the problem with Wikipedia today. While giving lip service to the good faith of volunteers, the admins themselves don't live it, and treat everyone that isn't an admin as an outsider. If WP can figure out a way to fix this, I expect a resurgence of the glory days. Until then, though, I just wait and see if it will devolve into tribalism. Once that happens, I'm sure a clear successor fork will appear, and I'll contribute there instead. The most oppressive admins don't seem to realize that their position of power is only as secure as the goodwill of the volunteers supporting them. Once the goodwill evaporates, as seems to be the progression, Wikipedia will be dethroned. I've seen it happen dozens and dozens of times in the open community, and I see no reason why it shouldn't happen here as well. A git-based WP would eliminate much of the problems that occur today, and that technology wouldn't be difficult to create. — Preceding unsigned comment added by 75.139.254.117 (talk) 21:30, 28 December 2016

You're confusing administrators with registered editors. This isn't the forum for talking about what's wrong with Wikipedia - try the Village pump. This is the page for discussing improvements to Field equation. RockMagnetist(talk) 22:47, 28 December 2016 (UTC)[reply]

At the IP. You wanted this to be an article or dab or dabconcept page. Then write it. Provide sources. The burden is on you to actually search the literature and edit the article. Instead of actually doing anything you lecture on trivialities (as if we didn't know), and whine on and on and on about how you are mistreated or misjudged. If you're going to post on this talk page, either provide feedback about the article as it progresses, or just stay off it. It is not for personal grievances. M ∧Ŝ c²ħε И_τlk 08:42, 29 December 2016 (UTC)[reply]

@Maschen: You have written a nice intro, but ironically it highlights some of the concerns that led us to remove this page in the first place. There are several generalizations (e.g., two uses of "usually"; one of "most of the time"; a way that field equations can be classified). They sound plausible, but it seems none of us here have the relevant expertise, so it worries me that you don't have specific sources to back them up; and it raises the spectre of original research. If we can't find sources for the generalizations, we should probably avoid them and focus on field equations in specific subject areas. RockMagnetist(talk) 19:10, 28 December 2016 (UTC)[reply]

I agree and dislike like how vague it is. The topic is very broad. The books include field equations almost entirely throughout, yet none of them give a thorough presentation on field equations in general (terminology, classifications, or even what qualifies as a field equation - is a diffusion equation a field equation also?).

We could expand some of the lead paragraphs into their own sections with examples of terminology/classification, I should be able to find citations for them. M ∧Ŝ c²ħε И_τlk 19:25, 28 December 2016 (UTC)[reply]

I think that's the right approach. I'm sorry I'm not more help right now - I'm just too busy with real life. RockMagnetist(talk) 19:45, 28 December 2016 (UTC)[reply]

Current version of the article[edit]

I cannot make heads or tails of the current version of this article (13 May 2017). On the other hand, the version as last edited by Maschen (2 Jan 2017) reads very well, in my opinion.

Perhaps the article should be reverted? Stigmatella aurantiaca (talk) 12:04, 1 June 2017 (UTC)[reply]

Thank you Stigmatella aurantiaca for taking an interest in this article. I agree it should be reverted. Not for my own vanity, but because it is not well presented any more.

"Continuity equations" are not usually classed as "field equations", "wave equations" are debatable to call "field equations" (sources?). Some of the sections are muddled and too narrow (the time evolution section is poorly written, "vacuum solution" at this point is too specific, we need more on the Einstein field equations or QFT to say anything about vacua). Some section headings could be kept if they were filled properly ("transformations" are not necessarily the same as symmetries if field equations are not invariant under C,P, or T reversal, also explaining "relativistic" vs "nonrelativistic" would be very helpful).

As is usually the case I have been meaning to add sourced examples, mostly from QFT, particle physics, and general relativity books, it hasn't happened yet. M ∧Ŝ c²ħε И_τlk 16:16, 1 June 2017 (UTC)[reply]

I am, unfortunately, familiar with 47.32.217.164. He fixed up Spacetime (after I had been working on it for six weeks) while I was out of the country, and I did a BRD to keep him from improving it further. Stigmatella aurantiaca (talk) 19:55, 1 June 2017 (UTC)[reply]

It's too bad, will try and help out with that and related articles... M ∧Ŝ c²ħε И_τlk 09:38, 2 June 2017 (UTC)[reply]

Before his current IP, he was 75.139.254.117 (talk). Most of his edits under his earlier IP were on topics on which I have no expertise and don't feel like touching (but maybe you can?), but some of his recent edits under his current IP, such as his contributions to Darlington transistor, are mostly worthless. He's gotten into edit wars and has gotten temporarily banned. Stigmatella aurantiaca (talk) 10:02, 2 June 2017 (UTC)[reply]

Bold Revert Discuss of Field Equation[edit]

Following wp:BRD, I have reverted the 13 May 2017 version of this article to the version as last edited by Maschen (2 Jan 2017). Stigmatella aurantiaca (talk) 16:37, 1 June 2017 (UTC)[reply]

@Maschen: @Rgdboer: We appear to have an obvious consensus, since, in addition to Maschen and myself, User:Rgdboer has thought it worthwhile to initiate edits on the reverted version. Stigmatella aurantiaca (talk) 22:42, 1 June 2017 (UTC)[reply]

FWIW, I reverted a change User:Rgdboer made. If a field is periodically disturbed, this will generate waves (as time and space varying configurations of the field). This totally separate from varying the Lagrangian or Hamiltonian density to derive field equations. This should also be clear from the first subsection also. M ∧Ŝ c²ħε И_τlk 09:38, 2 June 2017 (UTC)[reply]

New source?[edit]

One source which could come in the article soon is Fields, Flows and Waves: An Introduction to Continuum Models by Parker. It does contain a variety of phenomena, but its scope is fairly restricted (non-relativistic and non-quantum).

It seems this is as good as it gets. There seems to be no source which discusses all field equations in a unified way. M ∧Ŝ c²ħε И_τlk 10:12, 2 June 2017 (UTC)[reply]