Wikipedia talk:WikiProject Physics/Archive December 2011

This is an archive of past discussions on Wikipedia:WikiProject Physics. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Basic concepts of/introduction to ...

There is an AfD on Basic concepts of quantum mechanics that raises some important questions for many scientific articles:

Should there be separate articles for explanations at different knowledge levels?
If so, how many levels, and how can readers be guided to the level that is appropriate for them? RockMagnetist (talk) 23:51, 28 November 2011 (UTC)

I'll repeat myself: two levels (Quantum mechanics and introduction to quantum mechanics) should be enough; the former should be roughly aimed to senior undergraduate physics students, though the lead at least should be accessible to the average freshman and possibly to an interested high school graduate; the latter should be roughly aimed to people in the last year of high school, but the lead at least should be accessible to most literate people. For lower levels than that there's the Simple English Wikipedia, and for higher levels there's Wikiversity. If the current Introduction to quantum mechanics article is too technical, that's too bad, but that's not a good reason to keep three articles in the long term; try merging Basic concepts of quantum mechanics into there and shaving excessively complicated stuff off into the main Quantum mechanics article, instead. ― A. di M. 15:58, 29 November 2011 (UTC)

A. di M., where have you said this before? RockMagnetist (talk) 16:20, 29 November 2011 (UTC)

I don't remember exactly, but I think it was either on that article's talk page or here on WT:PHYS; it was a couple of years ago. ― A. di M. 16:25, 29 November 2011 (UTC)

I must say it is a bit absurd in my opinion that we should be aiming the general article on such a fundamental topic as this only to people who have had several years of college education in the subject. This is not how a general encyclopedia is supposed to work. It's supposed to be an overview of a subject, aimed at the layman. I think that any educated person should be able to hear about quantum mechanics on television or in the newspaper, and afterwards go to the Wikipedia article "Quantum mechanics" to get an introduction to the subject. By making an overly technical encyclopedia, we are just making an encyclopedia for its writers, not its readers.TheFreeloader (talk) 16:41, 29 November 2011 (UTC)

Speaking as a college student in engineering, having taken no pure physics courses beyond basic quantum mechanics (i.e. 2nd year college), I can say that quantum mechanics doesn't scare me in the least, and is definitely readable for any person who's taken at least a year of physics or chemistry at the college level. I'm of the opinion that the third article ("basic concepts") is overkill for introducing the topic... --Izno (talk) 18:41, 29 November 2011 (UTC)

I still think it is quite far from the accessibility an article like that should have. Take for instance the first paragraph in the Mathematical formulations section, if you ask me, that does seem quite dense. I think an article like General relativity is much closer to the level of accessibility an article like this should have. I think large parts of Introduction to quantum mechanics could quite favorably be moved to Quantum mechanics to make it more accessible. I don't think an accessible introduction to the subject should be hidden away in an article of its own.TheFreeloader (talk) 19:25, 29 November 2011 (UTC)

The problem is that there's a limit to what you can put into an article that's accessible to people who don't have a bit of background on the subject. To paraphrase an off-site essay, this is a topic that is explained to people over the course of several years of university-level study. Why would you expect it to even be possible to give a non-introductory description of it to a layman in a way that makes sense?

Physics and QM are beautiful and intuitive once you have enough of the concepts down, but that involves learning a way of thinking that's very alien to most people, and having scary amounts of math under your belt. If you want a treatment that's accessible to everyone, the "introduction to" articles exist for exactly that reason. Science is not simple.

By all means fix parts of the article that are unnecessarily cryptic. But if you try to make it accessible to people with no background, what you end up doing is either removing all non-introductory content, or having an article that's essentially an introductory and non-introductory article jarringly pasted together, for the cases I've seen over the years. --Christopher Thomas (talk) 21:47, 29 November 2011 (UTC)

Well, then I would much rather have an article which is only introductory, because again, that is what people are far most likely to be looking for when looking up "quantum mechanics". As I said below, if people already know a lot about quantum mechanics, they would not be looking up the main quantum mechanics article. An article in a general encyclopedia on a general subject is supposed to be an introduction, not an in-depth technical thesis. I think the Introduction to quantum mechanics article looks a lot more like an article in a general encyclopedia than Quantum mechanics does. Just look at the Encyclopedia Britannica article on quantum mechanics and tell which of the two article you think it looks the most like. As I see it the current Quantum mechanics article really is an article aimed at nobody, as the people who would understand it never would feel the need to look it up.TheFreeloader (talk) 22:03, 29 November 2011 (UTC)

They don't have to know "a lot" about quantum mechanics. They should know "a little", not "nothing", and have enough of an introduction to the math to follow the details. It saddens me that you feel non-introductory content does not belong in Wikipedia, because that'd lose most of the interesting content managed by WP:PHYS and almost all of the content managed by WP:WPMATH. The beauty of Wikipedia is that it isn't a lowest-common-denominator resource, but is instead a place where someone of any level of expertise can find something new to learn about. That's why we _have_ an "introduction to quantum mechanics" article, and on the other side why there's a mathematics of general relativity article.

If you are writing about a university-level subject, I think it's reasonable to target an audience of university students. However clear and eloquent the Feynman Lectures on Physics are, for example, you'd still lose pretty much any high school student you showed them to (because they didn't have the math, if nothing else). --Christopher Thomas (talk) 22:36, 29 November 2011 (UTC)

Your Encyclopedia Brittanica comparison is also misplaced. For physics-related topics, compare with Van Nostrand's Scientific Encyclopedia and the McGraw-Hill Encyclopedia of Science & Technology.

Wikipedia is not paper. We don't have to restrict ourselves to general-encyclopedia content - we have room to give more detailed treatments that will be more useful in any given reference area, and this is the _foundation_ of wikiprojects like this one.. --Christopher Thomas (talk) 22:46, 29 November 2011 (UTC)

Yes, Wikipedia can be more detailed. But that detail should never come at the cost of introducing the subjects properly. I also think WP:NOTPAPER is quite the wrong policy to cite here, given that the Britannica article clearly is longer than the Wikipedia article. So it clearly isn't space which is the problem. I'm not saying we should restrict our content only to easily accessible content, I'm just saying we shouldn't forget it, and we shouldn't hide it away. The simple and fundamental content should have top priority in articles on general subjects. The more technical content can then follow, and if there isn't room for it, it can be moved to other articles. Not the introduction. And you know, it's not the like the introduction to quantum mechanics article isn't about quantum mechanics, it is just as much about quantum mechanics as the main article, the only difference is that the introduction article starts from the right level and is organized in a logical progression.TheFreeloader (talk) 23:18, 29 November 2011 (UTC)

Simple English is not for native speakers of English who can't read very well. It's main target is people who perhaps do not have access to a Wikipedia article in their native language, know a little English and would like to improve it, and would benefit from an article where their math and physics knowledge (for instance) might help them understand the article, get the needed information, and also help their language competency. It is not a place to write down to the reader, but to write across to the reader.P0M (talk) 19:49, 29 November 2011 (UTC)

Indeed. Literate native English speakers should be catered to by the Introduction article. ― A. di M. 20:06, 29 November 2011 (UTC)

Quantum mechanics for dummies
Basics of quantum mechanics
Introduction to quantum mechanics
Quantum mechanics (main article)
Quantum mechanics (advanced level)

Count Iblis (talk) 19:07, 29 November 2011 (UTC)

I agree with A. di M. that two levels should be sufficient. And I think that the example with QM shows that. It seems to me that the main difference between Intro to QM and Basic QM is not the level of the material but the amount of non-QM stuff that is in the Intro article. In my opinion, they are 2 different forks of the intro to QM article, with the Basic QM being overall the better fork.

The only way I can see to add a third level of difficulty is for an Advanced Quantum mechanics rather than a more basic one. The three levels should correspond roughly to HS, College in related major, Grad school/experienced worker in the field.

As far as how to get people to the right level of article for them. We could try including the relevant information at the top of the article in an about template. (For a simpler version of this article see ...) If people don't read the about template, I suppose it is possible to make a template with a colored bar that goes across the template saying that alternate versions of this article exist at alternate levels. I am worried that articles are too busy with stuff like this as is, but I wouldn't mind making such a template for experimental purposes. TStein (talk) 21:01, 29 November 2011 (UTC)

There is a {{See introduction}} template in use on a few introductory pages, including Quantum mechanics. There are also Category:Articles with separate introductions and Category:Introduction articles (the latter is hidden for some reason). RockMagnetist (talk)

I don't think the main problem is that the Introduction to quantum mechanics article isn't visible enough, there's a link to it right at the top of the Quantum mechanics article, the problem is that the introduction article just seems a lot better written than the main article. The introduction article actually has a logical progression to it, while the main article seems more like a random jumble of information. If you ask me, what actually should happen is that the Introduction to quantum mechanics should be made the main article, then you can make the current main article could be made into your "Advanced quantum mechanics" article. The main article should be the generally accessible one, as that is what people are far most likely to be looking for when looking up "quantum mechanic". If you already know a lot about quantum mechanics, you would in all likelihood not be looking up the quantum mechanics main article, you would rather be specified and look up some specialized area or concept under subject of quantum mechanics.TheFreeloader (talk) 21:34, 29 November 2011 (UTC)

This suggests to me that a viable course of action would be ‘doing something’ to the current Quantum mechanics article (e.g. transwikiing it to Wikiversity), moving the current Introduction to quantum mechanics to Quantum mechanics, moving the current Basic concepts of quantum mechanics to Introduction to quantum mechanics, and polishing stuff up (including moving chunks around if they aren't in the article where they best belong). ― A. di M. 22:12, 29 November 2011 (UTC)

I don't agree with "transwikiing to wikiversity". There should be no upper bound on the difficulty of material that can be covered in Wikipedia. However, more specialized topics can be split out to more specialized articles. --Trovatore (talk) 22:15, 29 November 2011 (UTC)

I think that sounds like an excellent idea. Although I do think the Basic concepts article might have too much in common with the current Introduction article (as I see it, it's essentially just a shorter version of it) for it to need to stay around.TheFreeloader (talk) 22:19, 29 November 2011 (UTC)

That is not what Wikiversity is for. Wikiversity is intended as a collaborative environment where people can generate content for university-level lectures and textbooks. Synthesis and original work are encouraged there (within reason). Moving encyclopedic material there would rapidly turn it into non-encyclopedic material. --Christopher Thomas (talk) 22:42, 29 November 2011 (UTC)

OK, when the current AfD for “Basic concepts” is closed, I'm going to issue a multiple requested move. As a tentative title for the current “Quantum mechanics” article, I'm thinking of Advanced topics in quantum mechanics, but I'll accept better suggestions. ― A. di M. 15:08, 30 November 2011 (UTC)

I think that a rewrite of Quantum mechanics would be more useful than all these attempts to shuffle around articles. I am proposing changes to the article on the talk page. RockMagnetist (talk) 16:20, 30 November 2011 (UTC)

I am seeing broad agreement that Introduction to quantum mechanics is better written than Quantum mechanics, but most of the proposed solutions involve moving articles around. Why not rewrite Quantum mechanics, using Introduction to quantum mechanics as a starting point? I don't think Quantum mechanics is a good article for any audience. RockMagnetist (talk) 00:18, 30 November 2011 (UTC)

That might work too. I think one of the best things from Introduction to quantum mechanics is the way it explains the subject semi-chronologically, which shows the reader how each part of quantum mechanics were discovered by scientists. This was the way quantum mechanics was explained to me, and I think it is a common way to explain it because it makes clear how each counterintuitive claim in the theory came to seem like an inevitable conclusion. I know that in Wikipedia articles the description of a concept and its history are usually put into separate sections. But I think in this instance a lot is gained by having history and theory merged together the way it is done in Introduction to quantum mechanics.TheFreeloader (talk) 01:50, 30 November 2011 (UTC)

Can I suggest that, if anything, the best way forward might be to rewrite Quantum mechanics using Basic concepts of Quantum Mechanics as a starting point. Because it's so much shorter, it's actually a lot more readable and navigable than Introduction to Quantum Mechanics; which is important if there are other topics we need to add nodding references to.

The aim should be to make the article as simple and as short as possible -- so that (i) it is as easy as possible to read for people with no background in the subject; and (ii) it is as easy as possible to navigate for people who do have some background, so that they have to read as little as possible in order to find their way through to get to an appropriate {{main}} hatnote passing them to a detailed treatment of the aspects they are most looking for. The present "Basic concepts" article is actually a much better starting point in that regard, because its history is shorter and less detailed.

For each fact and each detail in the "Introduction to" article that is not in the "Basic concepts" article, the question we should be asking is: Can we leave this out? Can we, if at all possible, make this article shorter and leave the fact to a (well-signposted) appropriate second-level article instead? Essentially, can we apply WP:TECHNICAL at a whole-article level, with the ultimate result that our front-line Quantum mechanics article is as simple as possible, but that people can easily find their way to a properly detailed treatment of any aspect they may be interested in. Jheald (talk) 17:56, 30 November 2011 (UTC)

I would have hoped that the "Quantum mechanics" article could have the thoroughness of the "Introduction" article. But if there cannot be space for that, I guess the more superficial of version given in the "Basic concepts" article will have to do. What I find most important is that the structure of the "Introduction" article is kept, which it certainly is the "Basic concepts" article.TheFreeloader (talk) 02:56, 1 December 2011 (UTC)

Lagrangian and Noether's theorem

Can someone PLEASE help on these two articles? Detials are on the talk pages here:Lagrangian and here:Noether's theorem but basically there are sections which are unclear in nomenclature. I tagged Noether's theorem as being unclear. Lagrangian has a section which has been unclear for a long time. I'm making such a fuss over this becuase these articles are so important. They need to be clearer than they currently are.--Maschen (talk) 09:08, 4 December 2011 (UTC)

Reaction mechanics (again)

I developed REACTION MECHANICS. Yes it is new. It it is based on Newtonian Classical Mechanics. Indeed in the limit of no delay it reverts to classical mechanics. It is interesting to note that the Equation of Motion of REACTION MECHANICS reverts to the EQuation of Motion of Einstein's Theory of General Relativity. These are the two scientific theories that anker it. REACTION MECHANICS is derived by the same variational method as Euler Lagrange method of Classical Mechanics as well as the General Theory of Relativity. However, neither Classical Mechanics, Nor the General Theory of Relativity analize sytems with finite delay. REACTION MECHANICS extends these theories to systems with finite delay. I applied REACTION MECHANICS to an interesting Astronomical problem where it gives result in excellent agreement with observation. Thus, I thing REACTION MECHANICS is scientificallty besic sound. PLEAS, PLEASe show where REACTION MECHANICS is wrong. Yes it is new, so was Einstein's General Theory of Relativity. I still have some editing to doon it. Philipp Kornreich 13 December 2011 — Preceding unsigned comment added by 149.119.229.236 (talk) 20:16, 13 December 2011 (UTC)

It doesn't matter if it is right or wrong, or scientifically sound. It is original research. Original research is not suitable on wikipedia. IRWolfie- (talk) 20:41, 13 December 2011 (UTC)

If it is new, then it does not belong here. This is covered at WP:NOR, and has been explained to you at length already. Wikipedia is not a publishing venue. --Christopher Thomas (talk) 21:55, 13 December 2011 (UTC)

External link discussion

An editor is requesting feedback on links to an external site at WT:AST#Suggested Link. --Christopher Thomas (talk) 22:13, 9 December 2011 (UTC)

Molecular dynamics

Molecular dynamics needs a lot of attention to improve it. Anyone interested? Also a more opinions would be nice since my edits are being reverted. IRWolfie- (talk) 12:05, 11 December 2011 (UTC)

There is already an article that provides a list of MD software so it's pointless duplicating that list, I support you edits and will remove the list again.Polyamorph (talk) 04:24, 14 December 2011 (UTC)

Contributions need vetting

Could someone with more patience than I have take a look at the contributions of new user RiseUpAgain (talk · contribs)? I'm going to assume they're acting in good faith, but most of their cosmology contributions have been reverted and the rest look suspicious. --Christopher Thomas (talk) 01:01, 14 December 2011 (UTC)

People are usually left to ramble as they wish on talk pages, it's article edits that need to be examined. Xxanthippe (talk) 01:46, 14 December 2011 (UTC).

And their edits were almost entirely to article pages (the exception being Talk:Perpetual motion). Talk-page rambling is also usually cut short once it becomes clear that it will not result in improvements to the article. --Christopher Thomas (talk) 03:05, 14 December 2011 (UTC)

Higgs Boson article problem - expert needed to figure out what's correct

The article on the Higgs boson has two severely inconsistent statements. They need fixing but I have no idea what the correct description should be. Can someone look?

>> Talk:Higgs boson#Inconsistent statements on the Higgs Mechanism

Thanks! FT2 ^{(Talk | email)} 21:35, 14 December 2011 (UTC)

"energy flux density" redirect

Why on earth does the entry "energy flux density" redirect to the magnetic flux density article? This is electromagnetism, but energy flux density is more like thermodynamics, though in principle it could be anything up to radiometry and astronomy. It should really re-direct to the "energy flux" article, since energy flux is just power (energy flow/change per unit time), and the energy flux density is power per unit area (energy per unit time per unit area), dimensionally equivalent to intensity. Unfortunatley the terms flux and flux density can be mixed up and used interchangabley (this is a very annoying problem in the techincal literature)...

On a more general note, I think we need to decide how to deal with articles with quantitative names including flux an flux denstity: where they link and how to decide which definitions are used in the article (they split from source to source - look at definitions for mass flux, mass flow rate, volumetric flux, volumetric flow rate in any physics resources). My proposal is to use the more intuitive definitions, such as mentioned above, then mention in the article the alterntives.

P.S. I'm not good with re-directs, someone who knows how to deal with them should do this... -- F = q(E + v × B) 17:40, 18 December 2011 (UTC)

Done. ― A. di M. 18:07, 18 December 2011 (UTC)

Excellent, I checked it and it works. Thanks-- F = q(E + v × B) 21:04, 18 December 2011 (UTC)

Apparent weight

This article is not in good shape, but a few editors who initially wanted to delete the article and failed to do that (because they want to rewrite textbooks and delete the concept of "apparent weight"), now want to rediect it to the main weight article. Only they and I showed up at the discussion and one of them has declared consensus for redirection. Instead of taking the time to actually rewrite the article to make it better, they are playing tactical games with the rules, the concept of consensus etc. etc. Count Iblis (talk) 22:50, 21 December 2011 (UTC)

If you want to keep the article, start by citing a source that at least mentions the topic. So far, there's nothing there to indicate that it's even a potentially notable topic. It sounds like you have some textbooks you could use for that? Dicklyon (talk) 23:27, 21 December 2011 (UTC)

Yes, and I know that there are such textbooks. The real problem is that I don't have much time for Wikipedia (much less than about a month ago and that will remain the case until next Summer). I have the impression that a few vocal editors are hell bent on deleting/redirecting the article, one in particular has the habit of declaring consensus just because a few days has passed since a discussion was started and 2 or 3 editors who feel strongly for getting rid of the article managed to comment there. If this were newly created article, it wouldn't be a big deal, but this article has been here since 2005, many different editors have worked on it, but they are perhaps not as active as these few editors. Citations can always be provided, there are already a few in the article, I don't have a textbook that specifically uses the term "apparent weight", so I can't put in a citation myself, perhaps someone else here can. But as I just said, this probably isn't the real problem. Count Iblis (talk) 00:25, 22 December 2011 (UTC)

The article appears to be confused because it talks about the weight in an inertial frame. Inertial frames are by definition in free-fall. Thus there is never any weight in an inertial frame. JRSpriggs (talk) 02:47, 22 December 2011 (UTC)

The problem is, you're going to _have_ to find a textbook that "specifically uses the term 'apparent weight'" in order to demonstrate that the term is used. Per the weight article, the term "weight" without qualifiers is often used to cover this concept (as one of its two uses). Based on an admittedly-brief skim of the articles, my impression is that apparent weight should just be redirected there.

Sourcing is more important now than it was in 2005; believe me, I've run afoul of this too. This has had effects that are both good and bad, but fighting the shift is in my experience futile. About all that can be done is starting a wider discussion (which you've done by posting here), and finding references that use the term (which apparently hasn't been done if the debate is ongoing). --Christopher Thomas (talk) 04:38, 22 December 2011 (UTC)

Yes, I guess the best thing to do is to just rewrite the whole article from scratch with proper sourcing. I've made an offline copy of the current version and will work on the article offline. That saves me from having to engage with the arguments for deletion/redirecting and I can also work whenever I have time, otherwise every edit would have to be accompanied with reverting a redirect and that would be eventually be construed as edit warring. Count Iblis (talk) 14:53, 22 December 2011 (UTC)

Chi particle

So I was reading in the news today about a new state of the Chi particle had been found, Chi_b (3P). And I was going to head on over to the Chi article to see if info on it had been added yet and to add it myself if it hadn't. I found, to my surprise, we have no article on the Chi particle at all. Unless it's under a different name than Chi (should really have a redirect then). Considering what big news this is for the LHC, i'm certain people are going to be coming to Wikipedia to read about it, but they won't find anything.

I'd write an article on the Chi particle myself, but I know that particle articles often get technically complicated in both format and information. And i'm a biology major, not a physics major, so...who's up to the challenge of making the article? Even a quick one with a paragraph of information would be enough. I just need someone to set up the basics for me so I have some ground to stumble around upon and add info. Silver seren^C 19:59, 22 December 2011 (UTC)

It looks like it's in the summary table at the top of list of mesons (in the "bottom bottom" section), but not in the detailed data table. --Christopher Thomas (talk) 20:20, 22 December 2011 (UTC)

Well, there's more than enough sources out there to make a full article on it. And that's just with a general search with no digging. Anyone up to making an article on the Chi particle? Silver seren^C 20:35, 22 December 2011 (UTC)

Anyone? Bueller? Bueller? All I need is someone to make a paragraph that had the basic physics information on the Chi particle (information which I don't know) and then I can do my best to add other things to it, but I need that basic information first. Silver seren^C 22:30, 22 December 2011 (UTC)

Give it time. Even under the best of circumstances, it's usually days before a thread finishes getting responses, and people are going to be preoccupied over the holidays. The only reason I'm checking the wiki so frequently is because I'm procrastinating about cards and gift-shopping. --Christopher Thomas (talk) 23:25, 22 December 2011 (UTC)

Schrödinger equation slight re-write

What are other opinions of these proposed changes (by me)? -- F = q(E + v × B) 22:59, 23 December 2011 (UTC)

Black hole (again)

Remember the Preskill bet edit-warring at Black hole (edit | talk | history | protect | delete | links | watch | logs | views)? The user in question (JoetheMoe25 (talk · contribs)) is at it again, with a bit of help from 75.72.35.253 (talk · contribs · WHOIS). They're also now in borderline personal attack (vs User:TimothyRias and User:Jheald) and wikilawyer-threat (vs everybody) territory.

I'd given them a warning the last time this cropped up (in October), using one of the stronger versions (due to several other edit-warring warnings on their page). I've given them another warning at their new thread at Talk:Black hole.

That said, uninvolved eyes on this would help, especially if it escalates to blocking. --Christopher Thomas (talk) 05:51, 27 December 2011 (UTC)

Higgs boson nominated for Good Article

Some good news and a request for help!

The Higgs boson article has had a lot of work done and is getting stable, relatively consistent, comprehensive, easy to read, and balanced. As a top-importance popular topic, let's now get it to Good Article quality standard.

I've opened a section on its talk page and linked a few article contributors there to start it rolling. This is a general heads-up and call for anyone else at WikiProject Physics to get involved. Thorough review, fixes, and comments appreciated, and - shall we go for it :)

GA criteria are here.

FT2 ^{(Talk | email)} 10:03, 27 December 2011 (UTC)

Wavefunction query

This has been copied and pasted from user talk: Scorpion451, to gain a wider audience.

Hello. I know its very late to ask now 4 years on - though I only joined wikipedia several months ago. Recently I have significantly edited the wavefunction article. When looking through the (extremley negative) talk history, I found this statement:

"this page has no meaning because it doesnt give the formula for the wave function. The formula for the wave function grows to several pages long for any system containing more than a few particles. The problem is that it is a recursive simultanious equation. When one reaches the entanglement point it becomes nearly impossible to solve without the aid of computers simply because of the time it would take to write it down..."

I was wondering... what is this "formula for a wavefunction as a recursive simaltaneous (system of) equation(s)?" I thought wavefunctions are solved from wave equations (ex. Schrodinger, Dirac etc), but didn't think there was "a formula". I have yet to come across this, and have looked far and wide for it. If such a formula exists (I really don't think so...) could someone write down part of it (if its so long)? Please reply on my talk page when you can. Thanks. -- F = q(E + v × B) 14:36, 15 December 2011 (UTC)

I think what they are referring to is that to exactly solve the n-body wave function, you have to include all possible interaction terms, which grows as N^2. Because of this, it's pretty much possible to exactly solve the n-body wavefunction for any reasonably large number of particles. Because if this, people generally look at large systems with approximate solutions rather than exact ones. I'm pretty sure the page still has "meaning" but will also take a look at it later. Cheers a13ean (talk)

Right... thanks for explaining that. I had a hunch it was to do with the n-body wavefunction, but was unsure why it was brought up to include "the formula" then the mention of "more than a few particles" and "too long to write down". It was an odd post. Btw I am aware that for n-body systems the solutions to the Schrodinger eqn (e.g. for multi-electron atoms) requires (at present) approximative methods, like the Hartree-Fock and post HF methods - though I don't under stand them yet... =( Anyway thanks again =) -- F = q(E + v × B) 16:36, 15 December 2011 (UTC)

As far as I am aware, for any dynamical simulation of any physical system described by the TDSE, approximations are required to limit down the number of states. If there are counter-examples I would be interested (it sounds interesting) as I am mostly basing this off laser-matter interactions. IRWolfie- (talk) 22:17, 28 December 2011 (UTC)

Twin paradox input

Could use some input at Talk:Twin paradox#Propose to remove section. I'd like to remove some original research from Twin paradox#The time differential explanation in absolute terms by renaming the section to Twin paradox#In terms of Mach's principle and only keeping the last paragraph, which is properly sourced and relevant. The remainder seems to be OR/SYNTish, and about what new user Bernardbet calls the point of view of 'ether B' folks. TIA - DVdm (talk) 14:50, 29 December 2011 (UTC)

Thanks IRWolfie and D.H. for your input. I have made the proposed change after Berardbet had declared to comment no further. DVdm (talk) 10:29, 30 December 2011 (UTC)