Wikipedia talk:WikiProject Physics/Archive February 2012

File:Gravitational potential.gif

Hello all!

I do not know I someone is aware of this, but the graphic mentioned is a nice idea but actually wrong. It has several issues:

1. in the equation written we should have $|r|$ or we have to change the plot (may be even better just use positive r values in the plot)
2. the animation is wrong (!) it should be symmetric the behaviour it currently has is most probable due to numerical issues while making the simulation
3. may be others I've not spotted yet... ;)

In articles like Gravity well it is used at very prominent places and thus it should be either corrected (which I prefer) or removed.

By the way: A request to the user commons:User talk:Lookang#File:Gravitational potential.gif was not answered...

Greetings --DrTrigon (talk) 23:52, 17 December 2011 (UTC)

I agree that the diagram is not yet in a state appropriate for Wikpedia. Best removed. Xxanthippe (talk) 00:37, 18 December 2011 (UTC).

I am not really familiar with the rules here in enwiki... Shall I simply remove it or replace it by a given template? Is there something like a "quality management" here in enwiki? Greetings --DrTrigon (talk) 17:46, 21 December 2011 (UTC)

So I tried to fix the problematic things:

• increased the display time for the last frame from 30 to 300ms since in fact the animation is correct, but it was not visible (at least to me ;)
• changed the formula to include a modulus and now it agrees with the plot given

but in fact the best thing would be to cut the left side (negative part) and may be include the starting energy (which I assume to be 0, but this is not that clear at all). The corrected version was uploaded to commons. Let me know what you think now? Thanks and greetings --DrTrigon (talk) 12:28, 28 December 2011 (UTC)

By the way this holds for File:Gravitational field.gif also - did the same changes to this file. Greetings --DrTrigon (talk) 10:57, 15 January 2012 (UTC)

...and after thinking about it - it is still confusing... ;) I will remove them as soon as I have time and send a notice to the creator - may be he will check them again... greetings! --DrTrigon (talk) 19:18, 17 January 2012 (UTC)

I removed both animations from all pages here in enwiki and I left a message to the creator (and sent a mail to him). While going through all of them I found outher animations that should may be checked also:

• Electric field (lot of animations of same kind)
• Potential energy (1 static image of same kind)
• Newton's law of universal gravitation (other animations)
• may be we should check this list also

Any other opinions here? Would a notice on the images talk page be useful to inform other users? Greetings --DrTrigon (talk) 10:32, 19 January 2012 (UTC)

It would be better with just r in the denominator, as that is the way the equation is usually written. As it is now it looks like lrl. r is not the x-axis. The x-axis is displacement (signed) while r is the distance (always positive). Perhaps this can be explained in a caption. Nobody Ent 13:37, 19 January 2012 (UTC)

Yes (!) but the plot sugests negative values as there is the negative part of the axis plotted also... In fact the caption of the animation is the most confusing to me; what does the plot show? Force or energy (potential)?? Intuitively is clear, but reasoning about it confuses me... and that is bad... ;) Greetings --DrTrigon (talk) 12:19, 20 January 2012 (UTC)

Just to write down what Nobody Ent suggest; it is a 1-dim case (I suppose...) and $r=|x|$ holds... (assuming the horizontal plot axis is 'x') - still unclear whether the plot is force or energy. And what about the other pictures? --DrTrigon (talk) 17:50, 20 January 2012 (UTC)

can someone point me to a graphics that i can make an animation from my computer simulation? Lookang (talk) 06:29, 25 January 2012 (UTC) i still don't know what is the error after reading/browsing the discussion.

I'll try to summarize for you:

1. File:Gravitational potential.gif (your version) is not yet in a state appropriate for Wikipedia (let's forget the word "error"), because of:
   • the function plot does not agree with the functional term written in the text
   • related is the fact the in the caption is written "Gravity Field and Potential" and it is not clear what is what (I assume "Gravity Field" is an acceleration and "Potential" is the potential or energy, thus the first is the negative derivative of the second...?) - this is simply confusing
   • to me it looks like the particle coming from right moves to the left and passes the central mass moving further on the left (negative axis) side - which is due to the long arrow and the short display time form the last frame and again confusing (because if it passes the central mass it should oscillate - the other question would be why it passes, and so on...)
2. File:Gravitational field.gif (your version) the same here...
3. there are other articles containing such animations from you, namely:
   • Electric field (lot of animations of same kind)
   • Potential energy (1 static image of same kind)
   • Newton's law of universal gravitation (other animations)
4. and may be there are even more such animations... (did not check this)

To me it seems you are using a consistent convention, but either you use the one given in the article containing the animation (or picture) or you have to exactly write down your conventions within each animation in a form appropriate to be understood by everyone who understands the article in order to avoid confusion - do you agree? Greetings --DrTrigon (talk) 13:32, 26 January 2012 (UTC)

If an object falls into deep 1/R² potential well on a highly eccentric elliptical path, then it will whip around the central star and emerge on the same side from which it entered, not on the other side. JRSpriggs (talk) 04:58, 27 January 2012 (UTC)

This might be true (not familiar with that case) - but ... what do you want to tell us with this statement? (excuse me for not seeing the point) By the way what numbers of dimensions are you considering (2 or 3) and what do you mean with "on the same side", e.g. in 2 dimensions? Greetings --DrTrigon (talk) 13:38, 3 February 2012 (UTC)

Special:WhatLinksHere/Quantization (physics)

We can see such contexts for a link bound to "quantization" as:

• … spin angular momentum is quantized (i.e., it can only take on discrete values) … (at Stern–Gerlach experiment);
• … quantized energy spectrum … (at Quantum dot).

Of course, the article about quantization has little to do with spectra of particular quantum operators. Should this be just changed to discrete spectrum or there are more elaborate solutions? Incnis Mrsi (talk) 15:38, 1 February 2012 (UTC)

I most cases like these, the sentence should simply be phrased to say what they mean. This typically means not using the term "quantized" to mean "takes discrete values", since this is a form of WP:JARGON. (And one which is prone to be misunderstood.TR 16:34, 1 February 2012 (UTC)

Hmm. Discrete spectrum is two short articles glued together; the first one is related to energy quantization and the second is related to quantization of any quantum observable. It would be nice if it was just one or the other (I would vote for the second, but featuring energy quantization as an important example with optical consequences).

For now, I suggest linking to discrete spectrum in energy-related cases, and deleting the link in other cases (i.e., use the word "quantized" without having a link, but with having a parenthetical explanation).

I've also seen "quantization" link to quantum number but I don't think that's a good idea.

For angular momentum and spin quantization, I suggest linking "quantized" to Angular momentum operator#Quantization. :-) --Steve (talk) 14:18, 2 February 2012 (UTC)

Sure to link "discrete spectrum" for a discrete Hamiltonian? There is also energy level, and the "short article related to energy quantization" may be merged there, why not? Incnis Mrsi (talk) 14:24, 2 February 2012 (UTC)

Oh OK. So far I have...

• Either discrete spectrum or energy level (I have no preference) for energy quantization
• Angular momentum operator#Quantization Angular momentum quantization for spin and angular momentum quantization
• Charge quantization (which redirects to elementary charge) for charge quantization
• Whatever else I'm not thinking of. :-) --Steve (talk) 02:09, 5 February 2012 (UTC)
• Update: I made angular momentum quantization an article that redirects to Angular momentum operator#Quantization. A link to the former is nice because the section titles of angular momentum operator may be edited someday, and then there will only be one thing to change. :-)

Tachyon

One of the user has proposed that this article be split into Tachyonic field and Tachyonic particle. We are having a spirited disagreement over this matter. He/she claims is an expert on the subject however I am not. So, I am requesting expert opinion on this mater at the article talk page. We will appreciate your help Sumanch (talk) 17:20, 1 February 2012 (UTC)

Thanks for posting this, Sumanch. To make clear what my position is - the term "tachyon" is used commonly among specialists to refer Lorentz invariant field theories containing fields with negative mass squared (imaginary mass). Such fields do not under any circumstances propagate faster than light, even though a naive analysis suggests otherwise (they have superluminal group velocity, but this turns out not to correspond to the signal velocity). That fact has been understood at least since 1969 (the earliest reference I know of), and is now universally accepted among experts.

There's another usage of the term, common in science fiction, the press, and perhaps among non-specialists physicsts, that refers to particles that propagate faster than light. In Lorentz invariant theories such particles lead to very severe paradoxes (you can kill your grandfather), so very few if any specialists believe they can exist (note that in non-Lorentz invariant theories, this whole things takes on a different character).

The article as it was written conflated these two meanings- plus it needed work for lots of other reasons. So about three weeks ago I proposed clearly separating them. The only comments I got seemed neutral or supportive, and one suggested splitting the article into two. I did so (perhaps clumsily) - which brought on a flood of comments and edits.

In short: as a compromise, I propose we take the material that's currently in tachyonic particle and put it into tachyon, while leaving a disambiguation or see also tag that points to tachyonic field. The tachyon article should make clear that this is not a tachyonic field, and that such particles are widely believed to be impossible. Waleswatcher (talk) 20:06, 1 February 2012 (UTC)

Dispute at Talk:Universe

There is a dispute at Talk:Universe#The weasel word "believe"., regarding replacement of that word at Universe and Dark matter. This could use more eyes, as it's part of a larger debate about how science articles should be presented. --Christopher Thomas (talk) 06:54, 6 February 2012 (UTC)

Opinions on Dirac equation

Opinions are needed. A user calls it "crap" [1], and not yet responded to another user's query (well - its only been within several hours of course), see the talk section. The second user mentioned has edited the article extensivley to bring it to the current state (according to the edit history).--Maschen (talk) 10:32, 8 February 2012 (UTC)

Selected articles and images for Portal:Nanotechnology

The nanotechnology portal had laid abandoned for quite some time, but I'm now setting it up to automatically rotate through a selection of articles and images over the course of a year. I'm looking for some input on which content should be used; if you have any ideas, the discussion is at Portal talk:Nanotechnology/Selected article. Thanks! Antony–22 (^talk⁄_contribs) 02:13, 9 February 2012 (UTC)

Dark matter and black holes (again)

67.6.145.217 (talk · contribs · WHOIS) has recently become active at Dark matter, Cold dark matter, and Paul Frampton. This looks like the same user who was aggressively pushing intermediate mass black holes and primordial black holes as dark matter candidates a while back.

Someone else can vet their contributions, because I'm burned out right now. --Christopher Thomas (talk) 21:34, 3 February 2012 (UTC)

There is an ongoing talk page thread and a significant amount of back-and-forth editing at the article. More eyes would still be useful. This issue keeps coming up, over and over again, so it'd be nice to clearly establish consensus on what the article could say (to short-circuit future disputes of this type). --Christopher Thomas (talk) 19:32, 7 February 2012 (UTC)

Yes, please help - I'm getting tired! I tracked down something like eight recent reviews of dark matter physics. Not a single one mentions intermediate mass black hole as a dark matter candidate. Those that mention black holes or MACHOs (which black holes are one type of) say they are ruled out as DM candidates, both by microlensing data and other observations. These are 50-100 page reviews with hundreds of references. So I think it's a clear violation of wiki's due weight policy to give anything more than a passing mention (and probably not even that) to intermediate mass black holes - they're clearly a fringe idea pushed by one or very few researchers. Waleswatcher (talk) 02:42, 10 February 2012 (UTC)

After a little detective work, it appears that 67.6.175.184 and 67.6.145.217 are the indefinitely blocked user Dualus. Both IPs have been blocked for a week. Waleswatcher (talk) 05:16, 10 February 2012 (UTC)

Holographic principle and Hawking

This edit [2] changed, without any source, "Stephen Hawking presented rigorous theoretical arguments based on general relativity and thermodynamics which threatened to undermine these ideas about information conservation in the quantum realm. Several proposals have been put forth to resolve this paradox." to "Stephen Hawking presented rigorous theoretical arguments based on general relativity and thermodynamics which threatened to undermine these ideas about information conservation in the quantum realm, though the Holographic Principle is generally considered to have discredited Hawking's theory." Is that correct and even so shouldn't it be sourced? Thanks. Dougweller (talk) 19:20, 10 February 2012 (UTC)

I've reverted, based on your objections and my own misgivings about that statement. Information is expected to be preserved, but the holographic principle doesn't say anything about a) how or b) why Hawking's arguments would be incorrect. The editor can start a talk page thread (per WP:BRD) and produce citations if they feel otherwise. --Christopher Thomas (talk) 19:38, 10 February 2012 (UTC)

Thanks. Dougweller (talk) 19:47, 10 February 2012 (UTC)

That's actually pretty accurate. Holography, of which there are now multiple completely explicit examples, proves that (at least in those examples, which include pretty ordinary types of black holes) there is no information loss from Hawking radiation. Hawking actually publicly admitted he was wrong on that and settled his old bet about 6-7 years ago for reasons related to that (although ironically his stated reason for doing so is wrong, but never mind). I'm pretty sure I can find references for all of that, but it will take some time. Waleswatcher (talk) 22:35, 10 February 2012 (UTC)

With respect, that's a pretty garbled description. The holographic principle is not holography - it's a statement that you can construct a theory that encapsulates the behaviour of a system (including its information content) on a surface bounding that system, as an alternative to constructing such a theory in the bulk volume. This is known to be true for certain classes of theory (see AdS/CFT correspondence), but it is presently unknown whether it's true for the laws that govern the universe (as we don't _have_ a theory of everything to try applying such a transformation to).

The second part of what you're talking about is a reference to the Thorne-Hawking-Preskill bet. Hawking conceded the bet after writing a paper that he claimed showed that the region within an event horizon for certain types of black hole does not contribute to the evolution of the state of the universe outside of that horizon, which he interpreted as meaning the horizon never forms in the first place (or at least not one that permanently isolates information that falls in; he's offered a couple of different conjectures about that). While Hawking believes that his proof a) is valid and b) resolves the paradox, this is still being debated within the physics community.

Long story short, no support that I see for the holographic principle magically solving all problems with black holes. At best, it's circumstantial evidence for such a solution _existing_, but we have that already from black hole thermodynamics (the size of the horizon is directly proportional to the amount of entropy contained within the hole, growing as information-bearing matter falls in, and shrinking in a way that's pretty darn suggestive of information coming back out again). --Christopher Thomas (talk) 23:00, 10 February 2012 (UTC)

I made some changes. See what you think. Waleswatcher (talk) 22:55, 10 February 2012 (UTC)

Christopher - if my description is garbled, it's my poor communication skills. I agree with you that we don't know that our world can be described holographically, but then, we don't know that black holes Hawking evaporate either. And it's not that holography "magically" solves anything, or even identifies the specific problem with Hawking's computations - it's that it (more precisely, the specific examples of it that are known, mainly AdS/CFT) proves that there cannot be information loss, full stop, because the dual theory is explicitly unitary. Waleswatcher (talk) 23:16, 10 February 2012 (UTC)

The original idea was that the information in a chunk of matter which fell into a black hole was swallowed up by the black hole and thus could never affect the external world again. However, the holographic principle shows that information is not so localized in space as that. Rather the information is also distributed in the gravitational and other fields around the chunk and remains available outside the event horizon of the black hole so that it can affect the Hawking radiation as the black hole decays. Thus information and unitarity can be preserved. Thus black holes actually do have "hair", it is just down at the quantum level and so we do not normally perceive it. JRSpriggs (talk) 09:06, 11 February 2012 (UTC)

Commons

some issues about commons, which may affect astrophysics articles, have cropped up, see WT:ASTRO. 70.24.247.54 (talk) 11:47, 12 February 2012 (UTC)

Biophysics taskforce

Hi all, I'm working with User:Dcrjsr to run an editing workshop for biophysicists in a couple of weeks. We anticipate a large audience -- perhaps 50-75 working scientists who want to help edit. I am thinking about starting a new biophysics WikiProject to provide a workspace for them and future biophysicists... but alternatively, I noticed that there some active task forces in the physics wikiproject, so maybe we could simply start a biophysics task force, which might be better since we could rely on the existing project infrastructure to help out the newbies. Thoughts? Does the task force model work well? Would it be ok to start one? Or would there be interest in this community in working on a dedicated biophysics project? There is certainly enough to do on various biophysics articles, which of course are highly interdisciplinary. cheers, -- phoebe / (talk to me) 00:42, 11 February 2012 (UTC)

This is DcrJsr, commenting. The other natural home for the biophysics work would be WikiProject Molecular and Cellular Biology. I will put a query there, and work toward an agreement on how best to handle it. Is it sensible to have a subproject there and a task force here, which could perhaps concentrate on topics, or aspects of an article, related to theory and to experimental techniques? Dcrjsr (talk) 13:47, 12 February 2012 (UTC)

That seems a bit narrow. Why not WikiProject Biology? RockMagnetist (talk) 16:29, 12 February 2012 (UTC)

The WikiProject recommendations are that a wikiproject should cover several hundreds to thousands of pages, while a task force covers a few dozen to a few hundred pages. Based on Category:Biophysics, I would guess that there are 200-300 articles, so this subject may lean towards task force size. The right choice may depend on how many people commit to working on this and how many pages are likely to be added. RockMagnetist (talk) 16:39, 12 February 2012 (UTC)

I would start out as a task force. This is easier and has less organizational overhead since you can use a lot of the infrastructure already in place for the parent project. And if the task force turns out to be really active you can always branch off as a new project. Which project to choose as a parent is up to you. I don't think there would be any objections from this project, and I would be surprised if WP:Biology would object. (A taskforce within WikiProject Molecular and Cellular Biology does not seem that logical since there are areas of biophysics well beyond Molecular and Cellular Biology) If you need help setting things up I would be happy to help out.TR 18:44, 12 February 2012 (UTC)

After various consultations, WikiProject Biophysics has now been started, under Biology -- it has a skeleton main page, and we will be recruiting new participants at next week's Biophysical Society meeting. Any interested Wikipedians from Physics would be extremely welcome!! Dcrjsr (talk) 18:32, 20 February 2012 (UTC)

It's great that you're doing this! Generally only task forces have a parent, but this appears to be an independent wikiproject. You could list WikiProject Biophysics and WikiProject Physics as related projects.RockMagnetist (talk) 19:26, 20 February 2012 (UTC)

Tachyon article name (again)

Wiki's guidelines for article titles state: "However, when a topic's most commonly used name, as reflected in reliable sources, is ambiguous (can refer to more than one topic covered in Wikipedia), and the topic is not primary, that name cannot be used and so must be disambiguated."

I did a search (you might have to select "times cited" in the "or rank by" dropdown menu at the top) on inspires - a search engine for high energy physics scientific papers, the academic subfield relevant for any meaning of "tachyon" - for the most highly cited papers with a title containing the term "tachyon". Those are obviously reliable sources, being peer-reviewed scientific papers with hundreds of citations each. All of the top 25 papers use the term "tachyon" to mean Tachyonic field. Not one uses it to refer to a particle that goes faster than light, the topic covered in the Tachyon article. Therefore, it seems to me that the title of the Tachyon article "cannot be used and so must be disambiguated".

Therefore, I suggest Tachyon be moved to "Tachyon (particle)", and Tachyonic field be moved to "Tachyon (field)". Tachyon can remain as a disambiguation page pointing to those two and Tachyon condensation. Comments? Waleswatcher (talk) 23:46, 11 February 2012 (UTC)

GoogleScholar gives lots of hits for the tachyon (+causality) as FTL particle. So I would suggest letting the Tachyon article where it is, but to move Tachyonic field to "Tachyon (field)". --D.H (talk) 12:00, 12 February 2012 (UTC)

You searched for "tachyon causality", which is a key-word phrase for the particle meaning (there is no causality issue for tachyonic fields). Even so, some of those links are about one meaning, some about the other. If you search on google scholar simply for "tachyon", every single hit (at least on the first page, I didn't look further) is about tachyonic fields, not tachyonic particles - which establishes my point even more firmly. Even for "tachyon causality", almost all of the papers about tachyons as particles are pre-1970s.

The history here is that people got this wrong at first (early 1960s) - they thought tachyonic fields excitations were tachyonic particles, hence the origin of the naming confusion. That was shown to be false by a paper in 1969, the knowledge took a few years to percolate through the field, and it's now universally understood among experts. But the confusion in the old literature is still there of course, and there's tons of confusion among non-experts even today. That's part of why I'm pushing this - there's a problem here that wikipedia could actually help clear up.

Back to the point - as far as I can tell, the fact that a very large number of the most reliable possible sources (peer-reviewed papers with hundreds of citations) use the term to mean something other than what the article is about means that the name is in explicit violation of the part of the wiki guidelines I quoted. Am I misreading the guidelines? Waleswatcher (talk) 13:06, 12 February 2012 (UTC)

I think you are missing a crucial bit of the guideline ", and the topic is not primary,". The criteria for when a topic is primary are, unfortunately, rather vague. The crucial question to ask in this respect is: "What topic is a user looking up the term on wikipedia most likely looking for?"

In this case, if think there may be a good case to think that the tachyonic particles may be the primary topic. The reason for this is that the vast majority of popular science sources that mention tachyons are talking about particles travelling faster than light. Since people reading these sources vastly outnumber the people that have ever heard of tachyonic fields (which is pretty much restricted to people with a graduate degree in high energy physics), and these people are also fairly likely to be looking for stuff on wikipedia, it is fairly likely that somebody searching for "tachyon" on wikipedia is looking for a particle. (This is even more so, with the recent OPERA results sparking media interest in FTL particles).

Also, I think even under high energy physicists people are most likely to think of particles rather than fields when hearing the term tachyon. The fact that you do not see this when searching for research papers, is probably mostly a result of tachyonic particles being a (mostly) dead research topic since the general consensus is that they cannot be physical. The topic of tachyonic fields on the other hand is actually viable for research, hence most research articles talk about tachyonic fields. (With the exception of a bunch of recent OPERA related publications).TR 13:31, 13 February 2012 (UTC)

You're right - at first I didn't understand what that phrase referred to (I'm learning as I go here). But having read more discussions on this regarding other articles as well as the relevant wiki policy section WP:PRIMARYTOPIC, I see the following:

• A topic is primary for a term, with respect to usage, if it is highly likely—much more likely than any other topic, and more likely than all the other topics combined—to be the topic sought when a reader searches for that term.
• A topic is primary for a term, with respect to long-term significance, if it has substantially greater enduring notability and educational value than any other topic associated with that term. [My bold.]

Doesn't it seem that the bolded part of the second criterion is clearly violated here, considering the overwhelming usage of the term in the scientific literature to refer to a field with imaginary mass? As for the first, I certainly don't think "much more likely" has been established, or is even likely correct. Waleswatcher (talk) 14:44, 13 February 2012 (UTC)

A simple metric, to see if the current construction is directing users to the page they were looking for is to look at the page traffics statistics. On a typical day the tachyon article is visited ~1000 times [3]. The tachyonic field article is visited ~20 times [4]. This means that less 2% of the visitors of the tachyon page are using the hatnote because they have been directed to the wrong article. Apparantly, the vast majority of the users feel they have arrived at the right page. (Even if we take into account that a percentage will simply leave, if they did not land at the right page).

Of course, simple metrics like this are not the end all answer to questions like this, but the results here do give a certain inication what users are looking for.TR 15:49, 13 February 2012 (UTC)

I'm not sure that's a legitimate test. The problem I'm concerned with is that users might get funneled into the tachyon particle article, without necessarily even noticing that there is another meaning of the term or a physics issue here. The way the articles are structured now makes that rather easy, and your stats may simply reflect that fact (not to mention that Tachyonic field has only existed for a few weeks). But even if these stats did illustrate that users are likely to be looking for FTL particles, doesn't the fact the particle meaning seems to clearly fail the other main criterion matter? Waleswatcher (talk) 17:12, 13 February 2012 (UTC)

To your last question: No, not really.

To the argument that the Tachyonic field has only existed for a few weeks: That should not affect the traffic it gets now.

I agree, that such a test has its limitations. But in this case, the result is so heavily skewed that it becomes rather hard to argue that the majority of users looking for tachyon on wikipedia are looking for the tachyonic particle article. (Which is not surprising to me, since the amount of coverage that subject gets in popular science publications.)TR 22:07, 13 February 2012 (UTC)

• "To your last question: No, not really." Can you please expound on that? Here's a direct quote from WP:PRIMARYTOPIC: "A topic is primary for a term, with respect to long-term significance, if it has substantially greater enduring notability and educational value than any other topic associated with that term." You could either be saying (a) that it hasn't been demonstrated that tachyonic field satisfies that, or (b) that you agree it does, but you still don't agree it's primary even though the policy says so (perhaps because you think that form of primary-hood is outweighed by usage?). Is it one of those two? Thanks. Waleswatcher (talk) 23:52, 13 February 2012 (UTC)

Both topics have there own long term significance, demonstrated by the fact that both concepts have been used for decades, and both have their own educational use, demonstrated by the fact that both regularly get mentioned in textbooks. So, no the second criterion is not that relevant to this discussion.TR 12:44, 14 February 2012 (UTC)

We've established that the overwhelming usage of "tachyon" in the scientific literature over the last 40 years refers to the field. That's a pretty strong argument for primacy. So I disagree - I think it's clear that the field usage is primary, and the usage cannot be decided (see below). But in any case I'm not proposing to move Tachyonic field to Tachyon, I'm just saying we need to disambiguate the two. Waleswatcher (talk) 13:25, 14 February 2012 (UTC)

• This comment from Maghnus is rather spot on: "I support the proposal if Waleswatcher is correct about the Feinberg thing. If so, the current situation is a bit like having Energy talk about chakras and ley lines with a little hatnote pointing to other uses. " Waleswatcher (talk) 23:52, 13 February 2012 (UTC)

The big difference here is that tachyonic particles remain a valid physical concept, that is mentioned in pretty much any special relativity textbook out there, in addition to many popular sources. It is an unfortunate historical mishap that tachyonic fields use the same term, but it is also clear that that name derives from the primary meaning of the term (even if that derivation turned out to be a mistake).TR 12:44, 14 February 2012 (UTC)

I totally agree it's unfortunate, but we're stuck with it now.... Waleswatcher (talk) 13:25, 14 February 2012 (UTC)

• The current status on the talk page is that two editors now seem to think that no mention of tachyonic fields is to be allowed in any form whatsoever on the Tachyon page, even in the hatnote. That unfortunately makes the situation even worse than it was when I requested the move. Perhaps that's my fault, but regardless of fault, it's not good. Waleswatcher (talk) 00:14, 14 February 2012 (UTC)
• "To the argument that the Tachyonic field has only existed for a few weeks: That should not affect the traffic it gets now." Why not? Because it's very fresh it's linked to from very few if any other wiki articles, and it probably doesn't show up yet on many search engines (from which I suspect a large fraction of wiki's traffic originates). Its content is still pretty sparse, and it needs editing. And at the moment at least, it's hidden behind an opaque hatnote from the main article that leads to a disambiguation page. A true test would be to link both articles - Tachyon (particle) and Tachyon (field) - from a disambiguation page, and then see which gets more page views. But that probably won't happen (although the vote is 4-2 at the moment, so you never know). Waleswatcher (talk) 00:31, 14 February 2012 (UTC)

Even if it is fresh, if a significant portion of the visitors of tachyon was looking for tachyonic fields, would expect a significantly higher traffic on the tachyonic field page from people clicking on the hat note. (Even if you account for not everybody reading the hat note or not really knowing what they are looking for.)TR 12:44, 14 February 2012 (UTC)

Most users won't even know the Tachyonic field article is there (the hatnote currently says only "For other uses..."). Considering the fact that there is confusion among so many people over precisely this point, they have no way of knowing that they're not reading the correct article. As far as they know, those "tachyons" (that they heard about in a university press release or news report on a physics paper, perhaps) are faster than light particles, and look, here's a wiki article called "tachyon" about a subatomic particle. Why would they look any farther? I think that's an intolerable situation, and to avoid it there must be a clear and prominent statement (preferably in the hatnote, if not in the article name) that this term is very often used by physicists to mean something else. Do you agree with that, at least? Waleswatcher (talk) 13:25, 14 February 2012 (UTC)

Regarding which meaning of the term is primary: by (roughly) adding up citations I've provided evidence for something like 9,000 reliable sources (peer-reviewed papers in high energy physics, particle physics, and string theory) that all use the term in the sense of the material currently at Tachyonic field. None of the top 50 cited papers uses it in the sense of the material at Tachyon. As for popular sources, I've posted two at the talk page (there are more if needed). Here's the more verbose, from Lisa Randall's (a professor at Harvard) book Warped Passages, p. 286:

"The first problem....was that it contained a tachyon. People initially thought of tachyons as particles travelling faster than the speed of light (the term comes from...)...But we now know that a tachyon represents an instability...."

Waleswatcher (talk) 16:23, 15 February 2012 (UTC)

Again, those statistics do not say anything about what use is primary. It just says something about which is a more popular research topic. Still, when you ask a random physicist what they think of when you say "tachyon", most will tell you "a FTL particle". That is the original and most well known use of the term. That use however is not that popular as a research topic, because tachyonic particles are thought to represent something unphysical. (Please ask your self this question: "Which use of the term tachyon is the first you came across in your life?")TR 17:11, 15 February 2012 (UTC)

I understand that's what you believe, but you haven't presented evidence for it (apart from page views, see below). Instead, all the evidence that actually been presented points exactly the other way, including the use of tachyon in recent popular physics books (I've also found TV specials on physics and several other popular sources, all of which point the same way). As for what I it meant when I first heard the term, I have no idea - but in any case where I would want to be directed is to an article that accurately describes what physicists think about tachyons, not what science fiction writers in the 1960s thought.

As far as I know the only evidence presented against the move is the page view stats, but those do not support that side either. If someone hears about tachyons from (say) Brian Greene's book, they're likely to go to the wiki article named "tachyon" and read about a subatomic particle - and stop there. Why would they click on a hatnote link and follow it to yet another article when they seem to have already found the relevant material? Waleswatcher (talk) 18:59, 15 February 2012 (UTC)

Looking through special relativity textbooks that mention tachyons almost all (e.g. [5] [6] [7] [8] [9])use it in the sense of a hypothetical particle moving faster than the speed of light. The only exception I found was the Schwarz/Schwarz SR textbook, not surprisingly that serves an introduction to string theory.TR 20:53, 15 February 2012 (UTC)

I'm sure you didn't do that intentionally, but books on special relativity are a rather special case. Just as someone else searched for "tachyon causality" and came up with a few papers mentioning FTL particles, books on SR are much more likely to discuss that, because they can use it as an example to explain spacelike versus timelike momenta, and because tachyonic fields are too advanced a topic to be treated at that level.

But regardless, I do agree that some physics books and articles mention FTL particles. It's just that we've got (literally) 9,000 or so reliable sources using the term to mean the field compared to a handful using to to mean the particle. As evidence that the particle meaning is primary, that's obviously a losing argument. Then, we've got several very recent popular sources using it as a field, and even explaining in some detail (see the Lisa Randall quote) how people used to think it was a particle going FTL, but now understand it's not.

Again, I'm not trying to argue that the field meaning is primary, although I think the evidence overwhelmingly supports that - I'm simply asking for a disambiguation between the two. Waleswatcher (talk) 01:07, 16 February 2012 (UTC)

Wikipedia:WikiWomen's History Month and Lisa Randall

Lisa Randall would be a good project for Wikipedia:WikiWomen's History Month. GraniteStateGrump (talk) 06:16, 17 February 2012 (UTC)

Tachyon yet again

Having had their first attempt to re-factor Tachyon rejected, then their move request fail User:Waleswatcher is now rewriting the article to change its meaning to their preferred one, against the consensus established in two discussions. The discussion is here: Talk:Tachyon#The article is about the particle.--JohnBlackburne^words_deeds 19:14, 19 February 2012 (UTC)

The move discussion was over a proposal to change the name of one article to Tachyon (particle), the other to Tachyon (field), and split the material on imaginary mass fields from faster than light particles accordingly. One of the best arguments against that proposal was that fields of imaginary mass are referred to both as "tachyons" and "particles" in several reliable and very popular sources, including a NOVA television special and a book that sold over 1,000,000 copies. As such, the proposed name move probably wasn't the best idea.

Instead, the best course of action seems to be to keep things more or less as they've been for months (years?) in the article titled Tachyon - that is, include material on both FTL particles and imaginary mass - and simply explain the physics of both. Bear in mind that the term "tachyon" was coined in a 1967 paper on imaginary mass fields, and as a result the term has been used that way in (literally) thousands of reliable sources since. In addition, several very popular and recent books on physics define it that was as well. Just one example is Lisa Randall's book Warped Passages: "People initially thought of tachyons as particles travelling faster than the speed of light...But we now know that a tachyon indicates an instability." Waleswatcher (talk) 19:56, 19 February 2012 (UTC)

Note imaginary mass fields are only a part of Feinberg's paper, the paper is in general about the possibility of FTL particles. The first few sections are just about classical aspects of FTL point particles in relativity (also note that he explicitly introduces the term tachyon to refer to a particle that always travels faster than the speed of light in this part). It is only in the later sections that he proposes a field theoretic model for such particles.TR 22:09, 20 February 2012 (UTC)

Fully agreed. Unfortunately, as a result of that paper the name stuck both to FTL particles and to imaginary mass fields, and even to the combination ("tachyonic ghosts", for example). Waleswatcher (talk) 04:55, 21 February 2012 (UTC)

Properties of Bradyons

I proposed deletion of Properties of Bradyons (see my argument on the talk page). An IP user contested it. Should I go ahead and do an AfD? RockMagnetist (talk) 02:30, 15 February 2012 (UTC)

I'd stick a "mergeto" template on it instead, and a "mergefrom" template at massive particle, both pointing to a discussion thread on one of those articles' talk pages. The practical effect would be the same (discussion and result), but you'd preserve histories and so forth.

Someone might also want to have a (polite!) word with PsiEpsilon (talk · contribs). The "Bradyon" article was renamed "Massive particle" per talk page consensus. PE, presumably acting in good faith, decided to make the "Properties of (B|b)radyons" page and point the redirect at that instead. Given the rename discussion, this probably should have been talked over first, but PE is a very new user, so I can see how they'd have missed that. --Christopher Thomas (talk) 03:07, 15 February 2012 (UTC)

I merged the content from Properties of Bradyons to Massive particle and fixed the redirect. I'm a bit rusty on deletion policy, but since the content has been merged, I'll nominate Properties of Bradyons for AfD and see how it goes. -Anagogist (talk) 20:41, 21 February 2012 (UTC)

I added Properties of Bradyons to AfD; here's the discussion page. -Anagogist (talk) 22:18, 21 February 2012 (UTC)

Dephasing article

Could someone who understands this subject please take a look at this article and see if it needs to be split in two, reordered into sections, or whatever? Thanks. -- œ^™ 05:12, 21 February 2012 (UTC)

The effects discussed there are usually called decoherence in the physics literature, not dephasing. Probably dephasing should be merged with decoherence, or redirect to it. Waleswatcher (talk) 11:32, 21 February 2012 (UTC)

Yes, but I think people in the NMR field still use the term "dephasing". Count Iblis (talk) 16:17, 21 February 2012 (UTC)

If it is just a difference of terms that seems perfect for a redirect with a section in decoherence related to NMR specific issues. IRWolfie- (talk) 16:47, 21 February 2012 (UTC)

The people who want to understand dephasing for the purpose of analyzing NMR, optics, etc. need a very very different body of knowledge than the people who want to understand decoherence for the purpose of analyzing quantum-to-classical transitions, weak quantum measurements, etc. I think it would be difficult to satisfy both groups in one article. Of course, the current dephasing article is so small and lousy that it would be no problem to incorporate it into the decoherence article. But then if someone wanted to expand the NMR-type dephasing content, they would pretty much have to split the article back off. I would just as soon not merge them in the first place. --Steve (talk) 03:01, 22 February 2012 (UTC)

Elasticity (physics)

Elasticity (physics) is in astonishingly poor shape for an article of this importance. It is mostly just a string of dictionary definitions. RockMagnetist (talk) 23:53, 22 February 2012 (UTC)

"Dictionary definitions" is too generous. Here's a particularly good one

Elastic body - A body that has property of elasticity.

Waleswatcher (talk) 00:07, 23 February 2012 (UTC)

I just reverted the article to a version from January. It still needs a lot of work, but the January version looks to me like a better starting point and a much better article in the interim. Perhaps something can be salvaged from the February versions, or perhaps not. Waleswatcher (talk) 00:17, 23 February 2012 (UTC)

Thank you, Waleswatcher! That is a big improvement, and the stuff about the anagram is fascinating. I thought it was a hoax at first. RockMagnetist (talk) 01:20, 23 February 2012 (UTC)

Bare mass

The article on this was PRODded by Xxanthippe last week. I have looked at the article and, at least in its current state, it's not worth saving. However, the term "bare mass" is currently used in about a dozen Wikipedia articles and not defined in any of them. However, I don't have enough knowledge of physics either to try improving the article or to edit another article suitably to create a redirect target. So I've let the PROD stand, but the term really does need at least a redirect. Can anyone help? PWilkinson (talk) 20:51, 24 January 2012 (UTC)

Delete and purge inbound links from the main space. "Space free of all matter and fields" is something from an outdated paradigm. Problems with particle's invariant mass are too complex and specific to particular theories to be explained like in a secondary school. Incnis Mrsi (talk) 21:35, 24 January 2012 (UTC)

Keep and improve. As far as I can tell, it's linked from fewer than a dozen articles: aside from user pages that link it, it's linked from Four-fermion interactions, Seiberg duality, and Physics beyond the Standard Model. One article talk page (Talk:Consensus theory of truth) and a couple of watchlist-templates also seem to link from it, but the three articles listed above are the only ones I'd call relevant in this context.

That said, it's a term I've seen before, and one that I think there should be at least a brief article about. If I understand correctly, it means something along the lines of the mass a particle would have without the contribution from the disturbance it creates in the fields under which it has charge (e.g. mass of an electron minus any energy bound up in its electromagnetic field, mass of a quark minus energy in electromagnetic and Strong fields, etc). It's quite possible that I'm _not_ understanding the term correctly - which is one of the reasons I'd welcome an article about it.

In the context of the pages that link to it, it's usually linked from a phrase along the line of "this theory has chiral symmetry, and so no bare masses". An explanation of how exactly that follows and what its implications are would be a good thing to have at the bare mass article. --Christopher Thomas (talk) 21:43, 24 January 2012 (UTC)

I got rid of the PROD. It doesn't take much effort to find references to support the notability of this subject. RockMagnetist (talk) 22:00, 24 January 2012 (UTC)

It is related as to what the "bare mass" value of a neutron would be if it didn't have any stored free energy.WFPM (talk) 00:24, 25 February 2012 (UTC)

Big Bang

Hello, please see the discussion on the religious interpretations of the Big Bang. A couple users wish to remove the section in its entirety. Your comments on the section would be appreciated. Thank you, Anupam^Talk 02:22, 24 February 2012 (UTC)

Seems like another athiest fundamentalist POV push to remove perfectly fine content (like the holy crusade to ban the word "believe" that came through here a few weeks ago).TR 12:45, 24 February 2012 (UTC)

Please assume good faith before making disparaging remarks about other editors. IRWolfie- (talk) 13:49, 24 February 2012 (UTC)

A whole section on religious interpretations seems undue, I've proposed that a shortened wording be added to an existing section. IRWolfie- (talk) 14:32, 24 February 2012 (UTC)

"Athiest fundamentalist"? This is an article about a scientific topic. Per my comments in the thread, discussion about how religious scripture predating the model can be interpreted as applying to the model if you look at it sideways, has little place there. --Christopher Thomas (talk) 16:14, 24 February 2012 (UTC)

Philosophy is no less scientific than modern science. Do you object to including a section on a strictly philosophical interpretation of the Big Bang theory? One reason the Steady State Model, which the Big Bang theory then superseded, was so popular is that considering matter eternal appears to rule out the need for searching for a First Cause that creates or sustains the universe in existence. All of this can be argued scientifically with natural theology, a branch of philosophy based solely on reason and not on scriptures or religious divine revelation. See my comments there.—Geremia (talk) 16:43, 24 February 2012 (UTC)

"Philosophy is no less scientific than modern science" - sorry, what? Philosophy is certainly not science. Anyway, the section as written focusses on religion (specifically Catholicism), and as I said in the comments it doesn't make sense to me to include a section on the connections between the big bang and Catholicism while leaving out philosophy, Hinduism, Buddism, pop culture, the TV show, the Flying Spaghetti Monster, etc. Since adding all of that would significantly degrade the article by distracting from its core topic, I don't think any such sections should be there. People that want to read about religion or philosophy can click the appropriate "see also" links. Waleswatcher (talk) 17:15, 24 February 2012 (UTC)

RFC started

There is now an RFC on this subject. It's cross-listed as both a science and religion RFC, to get a broad cross-section of responses. --Christopher Thomas (talk) 02:15, 28 February 2012 (UTC)

Superconductivity

i really doubt whether the "critical temperature" in this context is the "critical point (thermodynamics)". This link in the article seems to be wrong--92.203.20.67 (talk) 21:00, 26 February 2012 (UTC)

I agree. One is crossing a phase boundary, but it is not generally at a point on the phase diagram where the boundary ends or forks. However, I do not know what other word or phrase to use to describe the temperature in question. JRSpriggs (talk) 09:53, 27 February 2012 (UTC)

"Critical temperature" is indeed the term used for it (unfortunate coincidence that the two terms are the same). It used to link to the critical temperature article, but that described the temperature at the critical point, and so was redirected to that article. It's probably best just to un-link the term within the superconductivity article. --Christopher Thomas (talk) 11:11, 27 February 2012 (UTC)

I linked it to Phase transition instead, where it's given as an example. Waleswatcher (talk) 13:14, 27 February 2012 (UTC)