Talk:Tachyon/Archive 3

Archive 1

Archive 2

Archive 3

Major problem - "tachyon" most often refers to a field with negative mass squared, and those do NOT propagate superluminally

I think the article should be re-written, or at least re-arranged with the tachyonic field material mentioned first and emphasized as the more important usage of the term. Or possibly there should be two articles - one for "tachyon" in the sense of a particle that travels FTL, and the other for "tachyon" in the sense of a field with imaginary mass.

Tachyonic fields occur all the time in physics - there's one in the standard model! The Higgs field at its uncondensed point is tachyonic, but obviously there's no FTL propagation in the standard model. There were papers at least as far back as the 1960's showing that negative mass fields don't propagate superluminally. Waleswatcher (talk) 01:02, 11 January 2012 (UTC)

It should be two articles. An article should only be about one meaning of a word. It's a jumble in it's current state Bhny (talk) 07:04, 30 January 2012 (UTC)

It is not obvious that "but obviously there's no FTL propagation in the standard model". No FTL communication, but that's a different matter, as the article explains. -- cheers, Michael C. Price ^talk 10:30, 30 January 2012 (UTC)

Well it may or may not be obvious - I retract that - but it's a fact that can be (and has been) proven rigorously. The same goes for any theory with any potential energy functional you like, including (or not) tachyonic mass terms, just so long as the kinetic terms are conventional.

Two articles is fine with me, I certainly agree it's a mess as is. Waleswatcher (talk) 21:01, 30 January 2012 (UTC)

Not a disambiguation page

I don't see why this was turned into a disambiguation page (a completely misformatted one). 'tachyon' is not ambiguous: it's not unclear what "a tachyon" is, and that article should be about that.

That the term has other uses in physics is not a problem. It's no different from what occurs time and time again on Wikipedia. We have an article System and an article Systems theory for example. So here we have tachyon, elsewhere we have tachyon condensation, and it's unlikely the two will be confused. As the names are clearly different there's no need to disambiguate them, and certainly no need for a disambiguation page.--JohnBlackburne^words_deeds 14:16, 1 February 2012 (UTC)

I agree, Tachyon is the theoretical particle. If there is a need for an article on tachyonic field, that can be created. There is no need for a disambig. page. A good analog for the attempted move will be to split electron into "electronic particle" and string theory analog of electric field.

I seriously oppose the move. Sumanch (talk) 14:48, 1 February 2012 (UTC)

PS — I propose to redirect tachyonic particle to this article.

The term "tachyon"is used routinely in physics to refer to a tachyonic field, which has more or less nothing to do with much of what is described in this article. If anything, the article titled "tachyon" should be about tachyonic fields. In addition, the article jumbles the two usages in an extremely confusing way. This was discussed here, and the consensus was that the material be split into two articles. I did that, creating "tachyonic particle" and "tachyonic field". There should be a disambiguation page. Waleswatcher (talk) 15:35, 1 February 2012 (UTC)

What consensus is there that it should be about tachyonic fields? That is a different name and a different topic. There's no need to split this article, simply return it to the state it was on Jan 5th when it was about the particle. Then have a separate article for tachyonic fields. As for 'tachyonic particle' that's rather like renaming 'electron' to 'electronic particle', pointless and confusing. The common name is 'tachyon' and that's what the article should be about.--JohnBlackburne^words_deeds 15:45, 1 February 2012 (UTC)

Please don't make changes. until this has been resolved. Sumanch (talk) 15:53, 1 February 2012 (UTC)

And two more things:

• moves shouldn't be done by cut-and-paste; see e.g. WP:CUTPASTE.
• a dab page is not needed for just two pages, see WP:TWODABS. A hatnote can be used if appropriate.--JohnBlackburne^words_deeds 15:55, 1 February 2012 (UTC)

It's not a different name. As I said, the term "tachyon" when used by high-energy physicists usually refers to a field with negative mass squared, i.e. a tachyonic field. Such fields do NOT propagate faster than light. Waleswatcher (talk) 15:57, 1 February 2012 (UTC)

Regarding cut and paste, I wasn't aware of the issue. Note that because the material on the page was jumbled between these two meanings, I did some un-jumbling (it wasn't just a block cut and paste). Waleswatcher (talk) 15:59, 1 February 2012 (UTC)

One more comment on the term "tachyon". I suspect the majority of people have no idea what it means. Of the rest, there are scientists working in the field of particle physics, and there are non-physicists that read science fiction of press accounts of physics. I suspect many of the latter think of a particle going faster than light when they hear that term, whereas the former think of the field (at least when they encounter it in a technical context). Waleswatcher (talk) 16:09, 1 February 2012 (UTC)

How high-energy physicists use the term is not as important as our common name policy: it is the way "tachyon" is commonly understood that's important, And the common understanding is overwhelmingly that it's a faster-than-light particle. See e.g. wikt:tachyon. "tachyonic field", and "tachyon condensate" are different topics. Looking at the history the meanings were jumbled as you jumbled them. But the page was still overwhelmingly on the particle. If it should be moved it should be done properly, following a move request as it's clearly contentious.--JohnBlackburne^words_deeds 16:12, 1 February 2012 (UTC)

You may be right that the more common usage is a faster than light particle (I'm honestly not sure that's true, but perhaps it is), and if wiki's naming policy is to use that, then OK. In that case I suggest deleting the "tachyonic particle" page I created, replacing this page with the material in that one, and then linking to the tachyonic field page. Regarding the jumble, I most certainly did not create that. The material in the article was already like that, I simply tried to clarify while waiting for comment on my proposed split here (which when it came supported it). Waleswatcher (talk) 16:18, 1 February 2012 (UTC)

'tachyonic particle' can be a redirect here (redirects are cheap), no need to delete it. Other than that I wasn't sure what jumble there was before your change: previously it started with a straightforward definition of a tachyon. Some of the later article may be unclear but that should then be fixed in the article.--JohnBlackburne^words_deeds 16:27, 1 February 2012 (UTC)

Do we agree to revert to Jan 5th edit and add a hatnote? Bhny (talk) 16:33, 1 February 2012 (UTC)

I would not revert so far back as it would lose a number of edits. Rather I would remove the section preceding the definition of a tachyon particle, though I note this was done already in the last version before it was last made a disambiguation page, so I would restore that.--JohnBlackburne^words_deeds 16:42, 1 February 2012 (UTC)

That's not acceptable. Considering that the primary use of this term among the people that actually know what it refers to is not a particle that moves faster than light, this article needs to carefully disambiguate the two meanings. Tachyonic fields shouldn't even be mentioned here apart from that, they should have their own article (if that's how we're going to arrange things). That means much of the material on this page needs to be heavily edited. I made a start at that in creating those two new pages. Waleswatcher (talk) 16:52, 1 February 2012 (UTC)

I'm not sure what you are objecting to. It doesn't matter how "people that actually know" use the term if common usage is different. The common usage is that it's the FTL particle, which is what this version says. If there is need for an article on tachyonic fields distinct from tachyon condensation then that should be created, but separate from tachyon.--JohnBlackburne^words_deeds 17:08, 1 February 2012 (UTC)

You're asserting with no evidence that that is a more common usage. Even if you're right, all I'm saying is that the article must disambiguate the two. AS it was, it conflated them rather thoroughly. I repeat - one possible solution to our conundrum is to replace the material that's currently in the article with the material in "tachyonic particle" (which is just a cut down version of what was in it a few days ago, with the material on tachyonic fields removed). Is that acceptable? Waleswatcher (talk) 17:30, 1 February 2012 (UTC)

In addition, the article on tachyonic particles (whatever it ends up being called) should make clear that such things are regarded as impossible by the vast majority of physicists, and the term is mainly used that way by science fiction writers or perhaps in the popular press. Waleswatcher (talk) 17:00, 1 February 2012 (UTC)

Ok! I pulled up one of the most popular undergraduate level Modern Physics book -

• Tipler, Paul A.; Llewellyn, Ralph A. (2008). Modern Physics (5^th ed.). New York, NY: W.H. Freeman & Co. p. 54. ISBN 978-0-7167-7550-8. ... so existence of particles v > c ... Called tachyons ... would present relativity with serious ... problems of infinite creation energies and causality paradoxes. {{cite book}}: Cite has empty unknown parameter: |1= (help)

Sumanch (talk) 17:55, 1 February 2012 (UTC)

That's a good quote for the article about tachyonic particles - it supports what I added earlier (that most physicists regard such particles as impossible). I agree that it also lends weight to the position that the more common usage (among the public or non-specialists) is tachyonic particles rather than tachyonic fields.

• So, this clears several things —

1. YTachyon is the accepted name for the hypothetical particle.
2. YTherefore, this should be the article for the particle and Tachyonic particle should be redirected to Tachyon.
3. YThe article should ha the following header.
   
   This page is about the hypothetical particle that travels faster than light. For the field excitation due to an imaginary mass, see Tachyonic field. For Tachyon condensation, see Tachyon condensation.
4. YTachyonic field and Tachyon condensation will develop as independent articles.

Sumanch (talk) 21:42, 1 February 2012 (UTC)

All OK by me.--JohnBlackburne^words_deeds 23:46, 1 February 2012 (UTC)

Can someone do the redirect from tachyonic particle? I don't know how. Waleswatcher (talk) 02:23, 2 February 2012 (UTC)

Done.--JohnBlackburne^words_deeds 11:30, 2 February 2012 (UTC)

D'oh ! It had already been done and I didn't notice, so set Tachyon to redirect to itself which is wrong in all sorts of ways. Restored it to before I made such a basic error.--JohnBlackburne^words_deeds 11:35, 2 February 2012 (UTC)

Let me reiterate one point - the standard model of particle physics contains a field with imaginary mass (the Higgs). Clearly, the SM does not have "serious ... problems of infinite creation energies and causality paradoxes". That should help make clear to anyone that still doubts that tachyonic fields do not propagate FTL. Waleswatcher (talk) 19:57, 1 February 2012 (UTC)

• YI don't think I had any problem with this part. Sumanch (talk) 21:42, 1 February 2012 (UTC)

Tachyon

I've moved this material from my talk page. Waleswatcher (talk) 16:57, 1 February 2012 (UTC)

This is my conversation with Waleswatcher on his/her talk page

Waleswatcher, please don't proceed with the changes until this issue has been resolved. I am not an expert on this subject but even with my little knowledge I can see that your reason do not hold. Sumanch (talk) 15:57, 1 February 2012 (UTC) I am an expert on this topic, and this move was discussed on the talk page already. Waleswatcher (talk) 16:00, 1 February 2012 (UTC) The reasons I am objecting is because you are not providing support for your claim (I am going to elaborate at the bottom) This is a High-importance article of WikiProject_Physics. You should start a proper dialog with the relevant project before such a large move. The discussion in the talk page was between three people, you, Michael C. Price, and Bhny. Bhny agreed with you and Michael C. Price did not dis agree. But I think for this article there is a need for discussion with expert and serious editors on the subject. I will open a RfC and find out what others have to say. Now for my first objection. I was only able to read the abstract of the Susskind paper; your main support for your argument that it's a fact that can be (and has been) proven rigorously- It says, We distinguish two fundamentally different types of superluminal (group velocity>c) behavior.... So, this means: Susskind is saying that he found one type superluminal behavior is causal and the other type is non-causal. Please see the key word group velocity. Group velocity, known as the modulation or envelope of the wave, exceeds the speed of light often and significantly (4c - 5c are not uncommon). Now Causality mean, in layman's term, I do something then the result happens. Ex. I speak .. you hear me speak. You do not hear me before I speak. Now, in Tachyon, the relative velocity of the particle in an Inertial frame of reference is >c. So, from STR this system is automatically and always non-causal. These are completely different subjects. So, the reference you have does not support your claim. I am not an expert on this subject and I don't know you. So I have to go by the reference you have provided. And your reference does not support your claim. Sumanch (talk) 16:46, 1 February 2012 (UTC) You've misunderstood the Susskind article. The point of it is that tachyons - meaning fields with negative mass squared - do not propagate faster than light under any circumstances. Superluminal group velocity does NOT imply superluminal propagation (as they explain) because you cannot form a localized wave-packet from a tachyonic field. Instead, the signal velocity (which is the velocity of propagation of all signals) can never exceed c for a tachyonic field, and the negative mass squared term simply represents an instabilty. Feiberg (two years earlier) got that completely wrong, but its now standard, and I can provide more references if needed. Waleswatcher (talk) 16:57, 1 February 2012 (UTC)

I am posting a note in Project:Physics and see if we can get more than one expert on this topic.Sumanch (talk) 17:09, 1 February 2012 (UTC)

OK, please link to it when you've done so. Waleswatcher (talk) 17:13, 1 February 2012 (UTC)

Project:Physics

Here is the Discussion I had posted. Sumanch (talk) 18:45, 1 February 2012 (UTC)

I'm coming in from Project:Physics. It looks like the rest of you may have worked this out. In my opinion, Sumanch's resolution looks good. Dilaton (talk) 09:05, 2 February 2012 (UTC)

8digit's edits

8digits is attempting to modify the language regarding breaking the lightspeed barrier, apparently because s/he thinks it might be possible to tunnel through it. This is problematic for many reasons:

(1) Neither of 8digits edits so much as mention tunneling, leaving the reader confused why the text seems to contradict the math in the preceding section.

(2) Tunneling through barriers with infinite energy is generally impossible.

(3) Tunneling to a different speed violates conservation of momentum, and hence is impossible.

(4) 8diigts provides no sources, and in any case, tachyons of this type are inconsistent with the known laws of physics on which tunneling is based.

One compromise (particularly given (4)) is to say that the math "appears to indicate" that it's not possible to break the barrier. Waleswatcher (talk) 13:33, 2 February 2012 (UTC)

Point by point (1) I think you should read some of the discussions about FTL and the CERN (2) Tunnelling in QM does not require infinite energy (3) Not necessarily true if one is talking about FTL (4) I added sources, and you removed them.

Since (4) is not true, and it may be possible that the maths "appears to indicate" that it may be possible to break the barrier.

Your compromise leads to the statement.

It may be possible that the maths "appears to indicate" that it may or may not be possible to break the light barrier. A statement with no meaning. 8digits (talk) 13:24, 5 February 2012 (UTC)

8digits (talk) 13:24, 5 February 2012 (UTC)

(1) I am extremely familiar with the topic. (2) I didn't say it did, read what I wrote. (3) Yes, necessarily. (4) Those references belong in a section about neutrinos, and do not support the material you added. Waleswatcher (talk) 15:17, 5 February 2012 (UTC)

8digits has now "added" duplicate versions of references that are already in the article (creating duplicates in the reference list), added material much of which is redundant with material that's already discussed, and placed it in a section where it doesn't belong. I removed it.

Moreover, the sources 8digits has "added" do not support the edits he is making. In those papers, terms are added to the standard model that break Lorentz invariance. There is no "light speed barrier" or any distinction between bradyons and tachyons once you break Lorentz invariance. For example, the kinematic equations that describe the energy as a function of velocity in the article depend on Lorentz invariance. There really should be a separate section to this article that makes that clear, with all Lorentz-breaking material included there, and not randomly mixed in with the rest. Waleswatcher (talk) 17:52, 5 February 2012 (UTC)

The lead sentence

As per WP:BOLDTITLE articles should start with a statement of what the topic is. The topic is tachyon, so the article should start "A tachyon... . We had the debate above and clearly settled on "tachyon" as the common name for the particle, so that should be the subject of the first sentence.--JohnBlackburne^words_deeds 16:34, 11 February 2012 (UTC)

No, that's a mistatement of the guideline. Here it is: "If an article's title is a formal or widely accepted name for the subject, display it in bold as early as possible in the first sentence:" In this case (a) it's neither the formal nor widely accepted name, it's at best more widely used for this than the other, but with significant possibility for confusion, and (b) in any case it's displayed in bold as early as possible while preserving clarity on what the article is about. I'm reverting back, please discuss here before making further changes. Waleswatcher (talk) 16:37, 11 February 2012 (UTC)

It is the widely accepted name. If it were not then, per WP:COMMONNAME, the page should be moved. But that was tried, by you, then reverted, as the consensus is that the common name for the particle is "tachyon". So that is the name of the article, and that should be the subject of the first sentence: 'as early as possible', as the guideline you quoted above says quite clearly.--JohnBlackburne^words_deeds 16:44, 11 February 2012 (UTC)

No. It is - perhaps - the more widely used meaning, and I agreed to compromise on the name on that basis. There is obviously a significant chance of confusion between the two. For example, prior to my edits the article badly conflated the two.

As for the guideline, "as early as possible" means as early as possible while preserving the meaning and clarity of the sentence. Quote: "If the article's title does not lend itself to being used easily and naturally in the opening sentence, the wording should not be bent in an effort to include it". Further quote: "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." Tachyon is clearly ambiguous by that standard, since a very large number of reliable sources use that term to refer to tachyonic fields. Finally, "Only the first occurrence of the title and significant alternative titles are placed in bold". In accord with that, I am going to bold "tachyonic particle" in the lead sentence. Waleswatcher (talk) 17:05, 11 February 2012 (UTC)

There was no compromise that 'tachyonic particle' is the more widely used name. The consensus is that the common name is 'tachyon'. As for disambiguating other articles that's what the hatnote does; it doesn't change how WP:LEAD applies to the article.--JohnBlackburne^words_deeds 17:56, 11 February 2012 (UTC)

First line and JohnBlackburne's edits

As discussed extensively above, there are two distinct usages of the term "tachyon", and it's very important that the article distinguish between the two. The consensus was that there should be two articles, tachyonic particle and tachyonic field, or tachyon (particle) and tachyon (field), but that change was reverted when additional editors got involved.

I'm OK with the naming as it is as long as the article is very clear on the difference. As such, it's reasonable - and in accord with wiki's style guidelines - to start the article with "A tachyonic particle, or simply tachyon,..." Waleswatcher (talk) 16:34, 11 February 2012 (UTC)

The title of the article, and potentially moving it

I agreed (see above) that this article could remain with the title "tachyon" while the article on tachyonic fieds is titled "tachyonic field" on the basis of the fact that the term "tachyon" is probably used more often to refer to FTL particles, and because that was represented to me as wiki's policy on article naming.

However, I have now read for myself the wiki guidelines, and found the following sentence: "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'm not certain what the phrase "and the topic is not primary" refers to, but iI seems to me that the two uses of the term "tachyon" meet this standard for ambiguity. For example, I did a search on inspires (a search engine for particle physics scientific papers) for the most highly cited papers with a title that contains the term "tachyon". http://inspirehep.net/search?ln=en&ln=en&p=t+tachyon&of=hb&action_search=Search&sf=&so=d&rm=citation&rg=25&sc=0 (you might have to select "times cited" in the "or rank by" dropdown menu). Those are obviously reliable sources, being peer-reviewed scientific papers with hundreds of citations in other papers. 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.

Therefore, it looks like the title of this article should be changed to follow wiki's guidelines. I suggest it be moved to "Tachyon (particle)", and the article "Tachyonic field" be moved to "Tachyon (field)". Comments? Waleswatcher (talk) 17:57, 11 February 2012 (UTC)

As noted above "Tachyon" is the common name for the hypothetical FTL particle. This may not be reflected in peer reviewed scientific papers because, as a so far undiscovered particle, it's not something people can do science on. But that's the common usage. There is no problem with having and article on such a topic; Wikipedia has articles on all sorts of topics which to a greater or lesser extent aren't part of mainstream science.--JohnBlackburne^words_deeds 18:16, 11 February 2012 (UTC)

Of course wiki can (and should) have an article on FTL particles, that's not what's at issue. The issue is the name, which as far as I can see clearly violates wiki's policies. To fix that, all we need to do is change is as I suggested earlier, and perhaps add a disambiguation page. Your assertion that FTL particles is the more common usage is more or less unsupported, but even if it's true, that's not wiki's standard (see the quotes from the policy above).

As for scientific papers, there are some (mainly from before 1969, but a few more recent) that are about particles that travel FTL, so it's certainly not the case that "it's not something people can do science on". It's just that there's a different usage of the term which is much more common (and note that tachyonic fields have also not been discovered, so that's not the point either). Waleswatcher (talk) 21:48, 11 February 2012 (UTC)

Which policies does it violate, and how? The two it matches are WP:COMMONNAME which says we should use the common name for article titles, and WP:CONSENSUS which says such things are determined by consensus. On which ten days ago Sumanch, I and Dialton all agreed. You also seemed to agree, suggesting that tachyonic particle should be a redirect here. I.e. the consensus is that the current name is the right one. It is really too soon to be re-opening this issue, unless you have some new arguments to bring to it.--JohnBlackburne^words_deeds 23:01, 11 February 2012 (UTC)

Please read my initial comment in this section. Wiki's policy states that "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." When every single one of the top 25 most highly cited papers in the relevant field use that term with a different meaning than the one here, that obviously meets that standard for ambiguity - and so "that name cannot be used and so must be disambiguated". Waleswatcher (talk) 23:06, 11 February 2012 (UTC)

Regarding consensus, I agreed that tachyon as an FTL particle might be more common. But having now read the policy, I've learned "more common" is not the basis for article naming. Quite the contrary, actually. bhny seemed to agreed with renaming and disambiguating, so counting you, Sumanch, and Dilaton on the other side it's 3-2 among editors that have commented, hardly a consensus. Waleswatcher (talk) 23:10, 11 February 2012 (UTC)

Actually Bhny proposed restoring this version, which was then about the last version where the article at Tachyon was clearly on the FTL particle. So if you're counting it would be 4-1. But that was not what I meant by consensus: we all seemed to agree ten days ago, including you, and everyone thought it resolved and concluded. And that meant we agreed that the common name, based on reliable sources, was "Tachyon".--JohnBlackburne^words_deeds 23:32, 11 February 2012 (UTC)

Well, Bhny suggested splitting the articles in the first place, so I guess we'd need to seek his/her input at this stage. I see you still haven't addressed the point, which is that, as far as I can tell, wiki's policy explicitly forbids this article being titled "tachyon". Waleswatcher (talk) 23:38, 11 February 2012 (UTC)

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: not moved, per current WP:COMMONNAME and current WP:PRIMARYTOPIC based on usage and long-term significance (examples in the encyclopedia links from Enric Naval). Agree with Waleswatcher that we cannot yet judge the WP usage of Tachyonic field. Once sufficient time has passed to see its usage, no prejudice here against a subsequent move if the field article usage does indicate a change in primary topic. (Or the re-merge might make that moot.) -- JHunterJ (talk) 16:07, 19 February 2012 (UTC)

---

Tachyon → Tachyon (particle) –

Summary: In 1967, G. Feinberg wrote a paper in which he coined the term "tachyon". In that paper Feinberg argued that wavepackets (i.e. particles) of fields with imaginary mass propagate faster than light (FTL). It was soon realized that Feinberg was wrong, and fields with imaginary mass do not propagate FTL. In the 45 years since, such fields - universally referred to as "tachyons" in the scientific literature - have assumed a very important place in theoretical physics. They play a role in the theory of superconductivity, and most prominently the Higgs boson of the Standard model of particle physics - the particle the Large hadron collider was built to find - arises when a field with imaginary mass condenses and breaks electro-weak symmetry. They are discussed in (literally) thousands of peer-reviewed scientific papers. References to fields of imaginary mass abound in multiple popular books, TV specials, press reports, etc. At the same time, the FTL particle (also called "tachyon") has caught the imagination of science fiction writers, and is used as an example for physicists of the bad things that happen when something goes FTL. There was a burst of interest in FTL recently because of the OPERA collaboration results. Unfortunately, the linguistic confusion created by Feinberg continues to this day. Many people conflate or confuse the two (including numerous wiki editors), and wiki's primary article is currently on the FTL particle rather than the field with imaginary mass. Because the FTL particle is not the primary meaning, I propose to move the name and use a disambiguation page. Waleswatcher (talk) 15:39, 12 February 2012 (UTC)

• oppose per WP:COMMONNAME. We don't base titles on usage in scientific papers in a narrow technical field if there's a common usage, as there is here, both within and without physics and as reflected by sources in the article.--JohnBlackburne^words_deeds 16:01, 12 February 2012 (UTC)

Thanks for the comment, but I honestly don't understand it. It seems to me wiki's policy is very clear: "...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)...that name cannot be used and so must be disambiguated." As for "narrow technical field", what are you referring to? This is an article about a hypothetical subatomic particle, and the search engines I checked (inspirehep.net and google scholar) search essentially all articles written in the field of particle and high energy physics. Waleswatcher (talk) 16:58, 12 February 2012 (UTC)

But there isn't 'more than one topic' that "Tachyon" could refer to. On it's own "Tachyon" is not ambiguous. To pick a plainer example we have an article on the country at China. That does not stop us having articles on China Airlines, Chinese language, China Miéville. In the same way having this article on the particle at Tachyon does not prevent us having articles on Tachyonic field, Tachyon condensation, Tachyon Publications, with suitable disambiguation.--JohnBlackburne^words_deeds 23:42, 12 February 2012 (UTC)

"But there isn't 'more than one topic' that "Tachyon" could refer to. On it's own "Tachyon" is not ambiguous." There are obviously two such topics - tachyonic particles and tachyonic fields - both of which are referred to simply as "tachyons" in very large numbers of reliable sources (at least in the latter case). There are literally thousands of scientific papers that use that term to mean "a field with negative mass squared", and I am certain that there are tens or hundreds of popular sources based on some of those articles, interviews with their authors, etc. That meets and exceeds wiki's standards for ambiguity as per the sentence I quoted above, and wiki's policy goes on to state that under such circumstance the title must be changed (that sentence of wiki's policy is something you've still not addressed, by the way). So if that's really the basis for your position, it's been resoundingly disproven and you should change your mind. Is that really the basis for your position? Waleswatcher (talk) 00:50, 13 February 2012 (UTC)

(←) Perhaps you can list some of those tens or hundreds of popular sources, with page numbers? The sources for the article as it is are in the article.--JohnBlackburne^words_deeds 01:03, 13 February 2012 (UTC)

I've already identified for you something like 35 sources of the highest possible quality (peer-reviewed and with hundreds of cites each) by doing a ranked-by-cite search for articles with "tachyon" in the title. Not one - let me say that again: not one - of the first page of resulting papers on two different search engines used the term "tachyon" in the sense of this article. There are plenty more of the same on successive pages of the search results.

If after seeing that you still assert that "there isn't 'more than one topic' that "Tachyon" could refer to", I don't see how providing you with yet more such sources is going to make any difference. I'm struggling to assume good faith on your part as it is. Waleswatcher (talk) 01:37, 13 February 2012 (UTC)

Again, where are the "tens or hundreds of popular sources" you are certain exist?--JohnBlackburne^words_deeds 01:53, 13 February 2012 (UTC)

You don't write thousands of scientific articles without generating press releases, news reports, mentions in popular books, etc. etc. Am I going to find some of them for you? Why should I? You've already ignored 35 or so of the most reliable sources there are, so what's the point? Waleswatcher (talk) 02:08, 13 February 2012 (UTC)

• Oppose. Under WP:PRIMARYTOPIC, we use the base term for the topic that the reader is most likely to be seeking. Number of journal papers has nothing to do with it. Tachyon gets at least 900 views a day, while tachyonic field gets 20 or less. Kauffner (talk) 06:33, 13 February 2012 (UTC)

• oppose WP:COMMONNAME common name is the particle Bhny (talk) 07:45, 13 February 2012 (UTC)

• oppose WP:COMMONNAME. Sorry that my comment messed things up before, it was simply a matter of forgetting about the time constraint, and being distracted by other work - and not refreshing the page before hitting the save button. -
  

I would describe myself as a fringe scientist and I have spent a lot of time trying to understand FTL geometries and FTL physics - and am particularly working on an FTL model of relativity. From the perspective of this research both types of tachyon are aspects of the same thing -I know this is O.R., but I also know that at least some descriptions of QM already use tachyons as virtual particles that definitely cross the FTL barrier. (its very hard to envisage gravity for instance without some kind of FTL interaction) - I would prefer things to be kept in a single article, but if it has to be separated would prefer a name something like "FTL Tachyon" or "Tachyon (FTL)" rather than "Tachyon (particle)", and maybe something like "Tachyon (Quantum)" for the field tachyon article, and the two articles really should cross reference each other. . . Lucien86 (talk) 12:16, 13 February 2012 (UTC)

• Comment: So we're just going to ignore WP:PRECISION? "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." Waleswatcher (talk) 12:39, 13 February 2012 (UTC)

• Guideline looks clear enough to me. In this case, the particle is primary. Primary topic is determined based on page views, links, and so forth, not RS. Kauffner (talk) 13:11, 13 February 2012 (UTC)

• The only way this article isn't in direct contradiction to wiki's naming policy is if the particle is the WP:PRIMARYTOPIC primary meaning. Here's one of the main standards for that: "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." The particle meaning clearly fails that standard. In fact, as we've seen the "field" meaning is the one used in the vast majority of highly cited scientific publications, and therefore has "substantially greater enduring notability and educational value". By this standard, Tachyonic field should be renamed "Tachyon".
• The other standard for primary-ness is usage. But since Tachyonic field has only existed for a few weeks and is only linked to by a hatnote, we can't judge on that basis. Waleswatcher (talk) 13:12, 13 February 2012 (UTC)

• Comment: :: The real issue here is that there is a major, persistant, and rather pernicious confusion between these two meanings. It started when Feinberg and others got this wrong (in published scientific papers) in the mid-60s - they thought tachyonic fields were tachyonic particles. That's when the term was invented and the whole thing came into the popular consciousness. Feinberg was wrong, and that's now universally understood by experts as the sources make clear, but it's not understood by the public. Or, judging by the state of this article before I edited it, by wikipedia editors. A disambiguation page would present people with a choice - which meaning are you looking for - ensuring that they realize that it could be either. Waleswatcher (talk) 13:12, 13 February 2012 (UTC)

• comment I reverted recent changes that obviously conflict with opinions here. This article is about a particle and the disambiguation goes in the hatnote not in the article Bhny (talk) 13:57, 13 February 2012 (UTC)

See the new section below. This discussion is independent of whether we should rename the article. Waleswatcher (talk) 14:14, 13 February 2012 (UTC)

• 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. Maghnus (talk) 23:09, 13 February 2012 (UTC)

Indeed, that's a rather apt analogy. I suspect that "energy" is more widely used by the public to refer to chakras than it is to the quantity conserved by virtue of the time-translation invariance of the laws of physics. Fortunately wikipedia's policies are carefully written, and a primary criterion for an article's name in such cases is its "enduring notability and educational value". Unfortunately, those policies aren't being followed here, at least not so far. Waleswatcher (talk) 23:37, 13 February 2012 (UTC)

If anyone doubts the fact that imaginary mass fields are called tachyons and that they don't go faster than light, see here. I don't know if that's published anywhere, but regardless it's a very brief review of tachyons in modern physics by an international expert (professor of physics at Brandeis U., formerly at MIT). A few quotes:

• "In some cases, however, the mass-squared turns out to be negative! Such a particle is called a “tachyon”."
• "According to the equations of special relativity, massive particles must travel slower than the speed of light, while massless particles must travel at the speed of light. If we apply the same equations to a tachyon, we find that it must travel faster than the speed of light! Needless to say, no such particle has ever been observed in nature."
• "At this point you might be tempted to conclude that any string theory that predicts the existence of a tachyon must be incurably sick, and should be rejected. But consider this: many conventional particle theories also contain tachyons—including the venerable Standard Model! In fact, what really happens when a theory contains a tachyon has nothing to do with particles travelling faster than light or any such nonsense." (goes on to describe Tachyon condensation and the Higgs boson). Waleswatcher (talk) 02:18, 14 February 2012 (UTC)

• Summary so far: As of now, there are 4 editors opposed to the move, 2 editors in support, no consensus. More importantly, please note that consensus on wiki isn't established by counting votes, but rather by discussion that refutes or supports the points raised. Of those opposed, only two have given more than a single phrase of justification for their positions:

• JohnBlackburne took the extreme position that "there isn't 'more than one topic' that "Tachyon" could refer to". That illustrates either a lack of understanding of the debate or deliberate attempt to derail it, since this is a discussion precisely about disambiguating Tachyon from Tachyonic field.
• Kauffner believes that WP:PRIME primacy for the particle meaning is established by usage, but hasn't responded to the fact that primacy of Tachyonic field is established both by usage among experts and by its clearly greater long-term significance, nor has s/he provided evidence for its greater usage (pageviews for the last two weeks or so aren't useful, since the two articles are on totally unequal footing in many respects, which is precisely the problem we're trying to address).
• The other two opposed quote WP:COMMONNAME (with no evidence presented), and haven't responded to concerns based on WP:PRECISION.
• As for the supporters, the position is clear - the term "tachyon" is used overwhelmingly in the most influential scientific literature over the last 40 years to refer to fields with imaginary mass. Readers will come to Tachyon searching for information on a topic in particle physics called "tachyons", perhaps prompted by a half-understood technical article or a news report or press release based on one. At the moment, those readers would have a hard time discovering that wiki's article is about something else entirely - it's about a mythical, unphysical particle popular with science fiction writers (and referred to as "nonsense" by Prof. M. Headrick, see the comment just above), not by the usage of the term as it is used overwhelmingly in modern physics. That's clearly a problem, and it must be addressed.

Finally, let me quote from WP:CON: "decision-making involves an effort to incorporate all editors' legitimate concerns, while respecting Wikipedia's norms.". The supporter's concern is clearly legitimate, and equally clearly it can be accommodated in any number of ways that respect wiki's norms. One simple fix is to move the name as requested, but there are other ways. I ask all editors to please respect wiki's guidelines and work together and compromise to help solve this problem. Thank you. Waleswatcher (talk) 14:33, 14 February 2012 (UTC)

More evidence: "tachyon" as a field with imaginary mass is overwhelmingly the most common usage in the scientific literature. I did a quick count using inspires, and there are on the order of 9,000 papers citing the top 50 papers that have "tachyon" in their title (see here for the second page of results). Every single one of those top 50 papers uses the term to mean a field with negative mass. So without accounting for redundancy, that's 9,000 reliable sources using the term to mean the field (redundancy will make that number smaller, but given that the top paper has over 700 unique cites all by itself, not by much).

How many reliable sources have been presented that use "tachyon" to mean an FTL particle? One (Tipler), on this page at least. And by the same token, tachyon as field is obviously the primary usage by the enduring notability and educational value criterion. So it's quite clear that Tachyonic field is the primary article, not the current Tachyon article. However, in view of the resistance to that I'm willing to accept as a compromise that neither is primary, and Tachyon is a disambiguation page, hence the move request. Waleswatcher (talk) 01:16, 15 February 2012 (UTC)

WP:TALKDONTREVERT: "consensus can be assumed if editors stop responding to talk page discussions" Waleswatcher (talk) 14:19, 15 February 2012 (UTC)

Editors have stopped responding as they've already !voted and made their points. There is no obligation on them to keep repeating their answers as you keep repeating yours. But FWIW my position is not 'extreme' but clear and policy based, as are other editors. If an editor just !votes without giving a reason then their !vote can usually be disregarded, but otherwise their arguments should be evaluated alongside all others.--JohnBlackburne^words_deeds 14:47, 15 February 2012 (UTC)

That's not wiki's policy, John. "consensus can be assumed if editors stop responding" Those opposed have not responded to the points and evidence presented, some of which is new and some of which is old. WP:COMMONNAME is not a justification for opposing the move, because it requires that the particle meaning be primary, which it is not. Unless that gets dealt with (or other points in opposition raised) in a reasonable time, I will move the article. Waleswatcher (talk) 15:01, 15 February 2012 (UTC)

No don't do that: per WP:RMCI involved editors should never close contested moves. Wait for an admin to get round to it after the full seven days.--JohnBlackburne^words_deeds 15:07, 15 February 2012 (UTC)

I didn't know of that policy - thanks very much for pointing it out. Now, are you going to address the evidence we've raised that the particle meaning isn't primary? The (literally) thousands of reliable sources that refer to fields with imaginary mass as "tachyons"? The fact that every single one of the 50 top cited papers in all areas of particle or theoretical physics use the term that way? The near-total lack of reliable sources presented here that use "tachyon" to mean the particle? Maghnus' point about energy? Waleswatcher (talk) 15:22, 15 February 2012 (UTC)

Comment: One of the most successful and best-selling authors of popular physics books is Brian Greene (a professor of physics at Columbia U.). From his book The Elegant Universe, p. 180: "...whose mass (more precisely, whose mass squared) was negative---a so-called tachyon." Greene is discussing to the tachyon of bosonic string theory, one example of the subject discussed at the article currently titled Tachyonic field. Waleswatcher (talk) 15:36, 15 February 2012 (UTC)

Note that Briane Green defines a tachyon (in the glossary of the book) as "particle whose mass (squared) is negative". Note the use of the word "particle".TR 08:40, 16 February 2012 (UTC)

Comment: Another author of some very popular books on physics is Lisa Randall (a professor at Harvard). From her 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) 15:45, 15 February 2012 (UTC)

Oppose The concept of FTL particles being called tachyons is extremely well known. A general member of the audience is much more likely to have enecountered this use (and look for it on wikipedia) than the rather more technical use in field theory to refer to an unstable point in the potential of a field theory. To illustrate how common this use is some popular physics resources on the internet: NASA: What are tachyons? USENET Physics FAQ World of Physics Encyclopedia of Science.TR 09:05, 16 February 2012 (UTC)

Timothy, your own sources contradict you. The USENET FAQ is about Tachyonic fields and explains why they don't go faster than light, and the NASA material points to the USENET article. Two out of your own four sources undermine your position. Waleswatcher (talk) 12:29, 16 February 2012 (UTC)

Usage is only one of the two criteria for primacy. The other (enduring notability and educational value) is a slam-dunk for the field meaning, as its overwhelming usage in the scientific literature over the last 40 years and several statements by experts shows. Regarding usage, the field meaning is used in several best-selling pop physics books I've quoted, as well as multiple TV specials, public lectures, etc. That material is all new or very recent, and has reached millions of people (literally, Greene's book alone sold over a million copies). Half of Timothy's chosen sources actually support the field view. Hence, "much more likely" for the particle meaning has certainly not been established, and so even ignoring the notability criterion for primary, neither usage should be regarded as primary. Therefore, by wiki policy we need a disambiguation page. Waleswatcher (talk) 12:01, 16 February 2012 (UTC)

Note, that many of those popular sources (for example Brian Greene's book) actually support the fact that the primary meaning of the word tachyon is a FTL particle. Also, many of those sources actually refer to the tachyon that appears in bosonic string theory. This is in fact a FTL particle, a bosonic string in its ground state follows (approximately) a spacelike trajectory. This, of course, we know is an indication that bosonic string theory is ill defined, because the no string state of the underlying (string) field theory is an unstable vacuum. Consequently, it is impossible form localized bosonic strings in their ground state in this theory.TR 12:28, 16 February 2012 (UTC)

"...many of those popular sources (for example Brian Greene's book) actually support the fact that the primary meaning of the word tachyon is a FTL particle." No, the tachyon of bosonic string theory does not propagate FTL. No excitation of string theory propagates FTL under any circumstances (and I can support that with huge numbers of reliable sources). You've been mislead by precisely the semantic confusion that needs to be disambiguated here, I'll add you to the list of evidence. And if you think material about the string theory tachyon should be discussed at Tachyon, then you're advocating a merge of those two articles, because any discussion of fields with negative mass is currently relegated to Tachyonic field (frankly, a merge would be better than leaving things as they are). Waleswatcher (talk) 12:44, 16 February 2012 (UTC)

You also seem to misunderstand the lasting endurability bit of the primary criteria. This clause is there to explain why the primary topic for big bang theory is the cosmological model, rather than the popular sitcom. (Both are notable and frequently used, but it goes to reason that the popularity of the TV show will go down once it stops airing.) This simply is not the case here. Both uses of the term clearly have enduring notability, so the clause simply does not apply in this case. So, you might as well stop quoting it again and again.TR 12:28, 16 February 2012 (UTC)

Sorry, but that's a mis-statement of wiki's policy. Here it is in full

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]

Tachyon as an FTL particle is mainly used in science fiction and press reports by writers that misunderstood the physics. Tachyon as a negative mass squared field is used in (literally) 9,000 reliable sources, is by far the dominant use of the term in science over the last 40 years, is used that way in several popular books written by experts, and now in a NOVA TV special. It clearly has "substantially greater" enduring notability and educational value. Waleswatcher (talk) 12:51, 16 February 2012 (UTC)

NOFI, but that is bull crap. Virtually any physics undergrad will learn that a tachyon is a FTL particle. Only HEP graduate students will learn about tachyons in field theory (and then only portion will learn about this.) TR 13:06, 16 February 2012 (UTC)

Unsupported opinion (perhaps rooted in your own personal history). That's not valid evidence by wiki's standards. What is valid evidence are the (literally) thousands of papers using the term to mean a field, and the complete lack of any usage of it to mean an FTL particle in all 50 (and probably more, I stopped there) of the top-cited papers with "tachyon" in the title. Not to mention the published opinions of several experts, who variously describe tachyons as FTL particles as "nonsense" and "originally what people thought, but...". Then there are your own references, two out of four of which in fact describe Tachyonic fields and further undermine your view. You yourself on this page have fallen victim to precisely the semantic confusion I'm trying to disambiguate (you thought the tachyon of bosonic string theory was an FTL particle). Do you really insist we need still more evidence that a disambiguation page is a good idea? Waleswatcher (talk) 14:08, 16 February 2012 (UTC)

Comment: Here's a TV special (NOVA, 2003) and interactive website that uses tachyon in the sense of Tachyonic field (see transcript, part 2). It was very popular and widely viewed on TV; the DVD on Amazon alone has 130 reviews. Waleswatcher (talk) 12:12, 16 February 2012 (UTC)

That actually again supports the particle sense of the term and I'll quote: "It's what's called a "tachyon," a particle that travels faster than light.". So again more evidence that that actually is the primary use.TR 12:33, 16 February 2012 (UTC)

They use the term particle, yes. But the quote is "Early string theory had a number of problems. One was that it predicted a particle...called a "tachyon"". They are discussing the tachyon of bosonic string theory, which is part of the material discussed on the page Tachyonic field and that the opposed editors here maintain can't be discussed at this article (because it's really not a particle, Lykken is speaking loosely). No form of string theory has faster than light particles. So, even you were just confused by the term. Do you really want wikipedia to perpetuate this confusion? Waleswatcher (talk) 12:39, 16 February 2012 (UTC)

The fact that they are using that phrasing (even if not 100% accurate) is writing on the wall that they consider the FTL particle sense of the term, the most likely to be known by their audience.TR 13:12, 16 February 2012 (UTC)

You have fallen victim to precisely the semantic confusion at issue. I can absolutely guarantee you that Brian Greene and Joe Lykken do not think that the tachyon of bosonic string theory (or any other field theory) is an FTL particle. Let me ask you this - if I prove to you (with reliable sources, math, whatever you prefer) that the tachyon of bosonic string theory is not an FTL particle (and that no one ever thought it was), would that change your mind? Waleswatcher (talk) 13:16, 16 February 2012 (UTC)

• I am afraid that most sources simply refer to "tachyon" as a FTL particle:

• Encyclopedias: Brittanica, Encyclopedia of Physics, Encyclopedia of space and astronomy, Encyclopedia Americana, McGraw-Hill encyclopedia of science and technology, Macmillan Encyclopedia of Physics, Workld Book Encyclopedia, even encyclopedias on other topics like Astronomy Encyclopedia, American philosophy: an encyclopedia. The ones that don't are much more specialized and will be seen by way less people: Concise encyclopedia of supersymmetry, Encyclopedia of mathematical physics

• Physics textbooks[1], [2], [3], [4], [5], with the exception of very specialized textbooks like A first course in string theory

• Scientific magazines New Scientist

• Scientific journal Nature has described "tachyon" as a FTL particle [6] and has used "tachyonic field" for the field [7]

"Tachyon" as a synonym for "Tachyonic field" only makes sense to a very tiny set of people. Any person not specialized is always going to associate the word "Tachyon" with the FTL particle, and only with the particle. So, the particle is the primary topic and I Oppose. --Enric Naval (talk) 01:01, 17 February 2012 (UTC)

"I am afraid that most sources simply refer to "tachyon" as a FTL particle" - that is certainly not the case, or at least you haven't come anywhere near to establishing it. I've posted evidence for thousands and thousands of reliable sources that use the term to mean the field. This paper alone has 720 citations from other papers that (obviously) use the term the same way. Every single one of the top 50 cited papers in physics with "tachyon" in the title uses the term to mean the field, and collectively they have on the order of 9,000 citations (I didn't bother to look further, but I'm sure there are many more). I've provided several quite popular and recent books that use the term that way, a TV special, and comments from experts that the FTL usage is "nonsense" and outdated. Waleswatcher (talk) 01:29, 17 February 2012 (UTC)

Right, but those are all scholar papers in one physics field. The immense majority of the population will never read any of them. --Enric Naval (talk) 03:45, 17 February 2012 (UTC)

It's not really "one physics field" - that search engine finds most physics papers written in the last 20 years, and just about 100% of those in any of the relevant subfields (particle physics, string theory, gravitation, relativity, etc.). I also tried google scholar (searched for tachyon), and I think every single paper on the first page of hits referred to the field meaning. Of course you're right that most people won't read those papers - but then, most people have never heard of tachyons at all. Of those interested in science, many, many people read the popular books I referenced. Greene's book supposedly sold over 1,000,000 copies for instance, Randall's sold well too, there was a TV special so popular that it re-ran at least twice several years apart, etc. On the other side, all we have are some brief encyclopedia entries and a few introductory physics books. Waleswatcher (talk) 04:24, 17 February 2012 (UTC)

Greene defines a tachyon as a particle (as mentioned above), which makes nonsense of your argument Bhny (talk) 06:09, 17 February 2012 (UTC)

The NOVA documentary also defines tachyon only as a FTL particle part 2 of transcript, which makes further nonsense. --Enric Naval (talk) 10:56, 17 February 2012 (UTC)

And the [USENET Physics FAQ] also defines it as a particle: "Tachyon is the name given to the supposed "fast particle" which would move with v > c.", and only mentions a "localized tachyon field" in the last paragraph. And the [NASA source], which refers to that FAQ, talks of tachyons only as a particle. --Enric Naval (talk) 11:11, 17 February 2012 (UTC)

We discussed this just above. Greene and the NOVA documentary are discussing the Bosonic string theory tachyon, which is a field with imaginary mass. In fact, it is one of the main examples discussed at Tachyonic field. As for [USENET Physics FAQ], you perhaps only read the first 1/3. Keep going. See that 'd'Alembertian with m^2 negative? That's the field equation for a negative mass square scalar field, i.e. a Tachyonic field (what's written there isn't quite right - it's not necessary to introduce quantum field theory, just classical field theory - but it's close enough), and it doesn't propagate FTL. And as you say, NASA points to USENET.

This is exactly the problem - as of now, three of those in opposition (you two and Timothy) have now fallen for precisely the semantic ambiguity that this move request is attempting to disambiguate. At the same time, several of you continue to maintain that there is no possibility of ambiguity, and that the meaning discussed at Tachyon is primary in the sense of usage - when you yourself cannot even distinguish the two or determine which sources are using it which way!

Perhaps it was a mistake when I split the articles in the first place, and they should simply be merged back to one. Waleswatcher (talk) 11:45, 17 February 2012 (UTC)

Comment: I just noticed the comment by Spatrick99 here on this talk page. It's completely correct. Waleswatcher (talk) 12:04, 17 February 2012 (UTC)

Along those lines, since there's such stiff (and frankly incomprehensible, but there it is) opposition to this move, I'm starting to think that the tachyonic field material should just be put back into the Tachyon article, and the whole issue discussed even more extensively in the lead, perhaps using Feinberg's paper that coined the term as a focal point. If desired, Tachyonic field can remain as the "main" article on that material, with a link from the new section that would be added to Tachyon. Waleswatcher (talk) 12:09, 17 February 2012 (UTC)

I think this is more or less reasonable, the historic attempt to provide a field theoretic description of tachyons should be mentioned, even as the fact that although the attempt failed, field of the type that was envisioned to produce a tachyonic particle excitation are still refered to as tachyons. The best practice for this type of situation is to have a WP:SUMMARYSTYLE section in this article with a {{main}} template link to the tachyonic field article. One of the advantages of such a setup is that the section here can be kept as accessible as possible, while the tachyonic field article can go more into the technical details (which obviously will be a little less accessible to a general audience because it will require some knowledge of field theory).TR 20:00, 17 February 2012 (UTC)

Of course I understand there are 2 meanings- and we now have these 2 articles, but how does it make sense to rename this article Tachyon (particle) when Greene etc. call the m^2 negative tachyon a particle too Bhny (talk) 12:08, 17 February 2012 (UTC)

I'm open to suggestions on the name! I suggested that because tachyonic fields (including the one Greene is discussing, he's speaking loosely) cannot really be thought of as particles, or at least certainly not particles that propagate FTL. Particles are localized wavepackets in a field, and tachyonic fields don't allow localized wavepackets to stay localized - instead, the moment you create a little disturbance at one spot it both spreads (at the speed of light) and grow exponentially in amplitude. So there's nothing you can really call a particle.

There's a wonderful (and quite literal) analogy. Imagine if you can a bunch of pendulums in a line, with the weight at the end of each connected by springs to the weights of those on either side of it. With all the pendulums hanging down at rest, if you wiggle one weight (like shaking the end of a rope) a ripple will propagate along the line from pendulum to pendulum, at a speed that depends on the stiffness of the springs and the mass of the pendulum weights. That ripple (or its quantized version) is a "particle" - literally (in the limit of lots of pendula you get a field theory in 1 spatial dimension). Now instead, imagine that at t=0 all the pendula are carefully balanced and pointing straight up instead of down (still connected by springs as before). They're so carefully balanced they'll remain pointing up unless you perturb them. Now wiggle one. What happens? Again, "ripples" propagate out, at exactly the same speed as before, mind you, but the pendula affected by the ripple start to fall over, and they gather speed very rapidly. So there's no localized ripple, there's the leading edge of a potentially catastrophic instability that grows exponentially with time. That's a tachyonic field. Waleswatcher (talk) 12:14, 17 February 2012 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Edit warring

We cannot not mention the field meaning of the term if we reference Feinberg or any of the other people listed there as early contributors to this topic. Feinberg's paper is about fields with imaginary mass. He's the one that originated the term. (And he's also the one, or one of the ones, that created this confusion in the first place.)

So, to those who want no mention whatsoever of the "field" meaning - what do you propose? Shall we strip everything out of the article that mentions physics at all? Shall we remove the material on the origin of the term? I'm at a loss here. Waleswatcher (talk) 14:12, 13 February 2012 (UTC)

Repeating what myself and others have said- An article is about one thing and disambiguation goes in the hatnote. Also you have to be careful because your revert count is at 5 which could get you banned (which I would hate to happen) Bhny (talk) 14:21, 13 February 2012 (UTC)

I reverted twice, actually. As you can see if you look, the other edits aren't reverts, they're constructive edits to other parts of the lead/article. If you want to edit the article, please do so selectively rather than with wholesale reverts. Thanks.

You have no comment regarding the fact that the article already devotes considerable space to discussing the "field" meaning (every reference to Feiberg, Sudarshan, the origin of the name, etc.)? Waleswatcher (talk) 14:29, 13 February 2012 (UTC)

Yes, this is about the particle, called tachyon. A search is not a reliable source. There is a link to tachyonic field in the hatnote, about as prominent as there could be.--JohnBlackburne^words_deeds 14:27, 13 February 2012 (UTC)

No compromise from you, I see, just wholesale reverts of all the changes, including those that have nothing to do with this. And no comment on the fact that the article already discusses the field meaning at length, in the lead? As for whether searches are reliable sources, that's not obvious, particularly for this case. I see you also have no comment on the fact that the article includes references to Feinberg (the person that coined the term in the first place), Sudarshan, etc., all papers about quantum fields with imaginary mass? Waleswatcher (talk) 14:33, 13 February 2012 (UTC)

Proposed changes

Following the discussions above, it's clear that any changes I make to this article are likely to be contentious, so I'll make some suggestions here first and ask for comments. I think the article would benefit from the following changes:

• Some overall language tuning, rearranging of sentences and paragraphs for clarity, etc. (I made a bunch of such changes, which were unfortunately wholesale reverted.) For example, the special relativity stuff shouldn't be in the lead paragraph.
• A new section on microphysical models. This would include, with sources of course

• Lorentz violating models (if you break Lorentz invariance, the speed of light ceases to be a barrier). Many of the models that seek to explain the OPERA results fall in this category. It needs to be made clear that many of the statements in the article (all the stuff based on special relativity) don't apply to these models.
• Field theory models in which the mass is imaginary. The original paper that coined the term "tachyon" was about this, there would just be a brief mention of the fact that this doesn't actually allow for FTL particles.
• Field theory models in which the kinetic term is modified, rather than the mass. This does work in the sense that there can be FTL excitations, although it's physically bad for all the usual reasons.

• Restoration of the lead sentence as it was Feb 11th, bolding the alternative title "tachyonic particle" as per [8].
• A re-write of the hatnote, to make it more clear that the exact same term - "tachyon" - is used routinely to refer to something else, at least in the technical literature, and that a reader looking for that usage should go to Tachyonic field.

Does anyone object to any of these? If so, please be specific. Thanks. Waleswatcher (talk) 15:39, 13 February 2012 (UTC)

On the last point no, this is not how articles work. This article is about the FTL particle, not about all uses of the term. WP is not a dictionary, so does not strive to include all meanings of a term in an article. Where a topic is related it may be mentioned and linked in context, appear in a template or included in a 'See also' section. If there is a chance of confusion with a similar name a disambiguating hatnote is used.--JohnBlackburne^words_deeds 15:55, 13 February 2012 (UTC)

"...this is not how articles work...If there is a chance of confusion with a similar name a disambiguating hatnote is used." The last point is about the hatnote. So..... huh??? Waleswatcher (talk) 16:57, 13 February 2012 (UTC)

• Proposed rewrite of the hatnote. Current form: "This article is about the hypothetical particle that travels faster than light. For a field excitation with imaginary mass, see tachyonic field. For tachyon condensation, see tachyon condensation." First draft propsed form: "This article is about the hypothetical particle that travels faster than light. For the usage of "tachyon" in high energy physics (a field excitation with imaginary mass), see tachyonic field. For the instability such fields represent, see tachyon condensation." Waleswatcher (talk) 17:01, 13 February 2012 (UTC)

The hatnote is already relatively long and verbose. The point of a hatnote is simply to link to articles the reader may have been looking for. i.e. they should already have some idea of the article's name and content. Probably it should be turned into a disambiguation page as there are other pages with 'tachyon' in the title, and other uses for the word in addition to the two in the hatnote now.--JohnBlackburne^words_deeds 17:26, 13 February 2012 (UTC)

I completely agree that "Tachyon" should be a disambiguation page, in fact I think that's required by wiki policy. But since you will not allow that, the hatnote needs to reflect the significant ambiguity here - the fact that there is another usage of the term, a usage that's by far more common in the physics literature. Many users won't know there's even the possibility of such an ambiguity, and this page needs to clearly inform them. Waleswatcher (talk) 18:53, 13 February 2012 (UTC)

You misunderstood me. If there's a clear primary topic as there is here the disambiguation page has the same name but with '(disambiguation)' in the page title. It's clear we need it, as there are are quite a few other pages in addition to the two currently in the hatnote that need linking to. So I've gone ahead and created it: Tachyon (disambiguation).--JohnBlackburne^words_deeds 19:20, 13 February 2012 (UTC)

There quite plainly is not a clear primary topic, and asserting so really doesn't seem to be in good faith. The problem is (sadly) getting worse and worse - a reader who has heard about tachyons in some physics paper or in a press report on a physics paper is very likely to get at totally wrong impression from this article. I'll hold off on editing it for a while, but I'm going to do my best to fix that problem. Please try to work with me in a good faith effort to improve the article. Thank you. Waleswatcher (talk) 21:51, 13 February 2012 (UTC)

(←) User:Kauffner addressed the primary topic quite clearly above, while others including myself looked instead at naming policies and found them in accord with keeping the article as it is. So please don't make changes based on your disagreement with this consensus. Given the broad agreement above it's time I think to close the debate and move on.--JohnBlackburne^words_deeds 22:04, 13 February 2012 (UTC)

Unfortunately, moving on is precisely what you're not doing. Instead, you're acting as though you want to erase the fact that there are two meanings of this term, and the article is about only one. The other meaning, also referred to as by the exact same name and which we've established unequivocally as the primary meaning in the scientific literature, must be disambiguated from the material discussed in the article about FTL particles. The hatnote is the only place you'll permit that, and now you've edited even that to make it harder to discover. I don't agree with that, and will edit it after a cooling-off period - if you engage in another edit war over that, we'll have to take it to formal arbitration. I hope that won't be necessary and you'll work with me in good faith to improve the article. As for the consensus above, it's in regard to the proposed move of the article name, not the text of the hatnote or the disambiguation page or the text of the article. Waleswatcher (talk) 22:54, 13 February 2012 (UTC)

The problem with disambiguation within the hatnote is there are many more than three articles to disambiguate, as you can see at the disambiguation page. It's usual to use a disambiguation page even with three articles (if only two then hatnotes can be used, per WP:2DAB). It's essential with 14 as there are on the disambiguation page now.--JohnBlackburne^words_deeds 23:06, 13 February 2012 (UTC)

Then I'm afraid we have a problem. Perhaps you'd be interested in helping to solve it? Waleswatcher (talk) 23:27, 13 February 2012 (UTC)

John, I see that there is a wiki template that seems specifically designed for this situation. The code for it would be something like this:

This page is about hypothetical faster-than-light particles. For the usage of "tachyon" in high energy physics, see Tachyonic field. For other uses, see Tachyon/Archive 3 (disambiguation).

Would that be an acceptable compromise? Waleswatcher (talk) 00:08, 14 February 2012 (UTC)

But given the usage stats that's unlikely to be the most sought after other use for those reaching this article. It's especially unnecessary as tachyonic field is prominently mentioned in the lead.--JohnBlackburne^words_deeds 01:01, 14 February 2012 (UTC)

I don't think the usage stats are meaningful. The tachyonic field page is very fresh - it has few if any other articles linking to it, search engines might not have indexed it, etc. Moreover, at least for the moment it's hidden behind a very terse hatnote that leads to a terse disambiguation page. Third, the whole problem here is that many readers may not know what they're looking for, and might (rather reasonably) assume that wiki's article entitled "Tachyon" about a hypothetical subatomic particle corresponds that physics paper or press release on "tachyons" that they wanted to understand - when in fact it does not. Last, the "tachyonic field" article is the primary article for "tachyon" with respect to long term significance as per WP:PRIMARYTOPIC. As such, at the very least it should get an explicit mention in the hatnote. Waleswatcher (talk) 01:32, 14 February 2012 (UTC)

We don't know what the primary topic for tachyon will be in the future. Maybe tomorrow someone will discover real tachyons and this article will be most read physics article on WP for a while. Maybe tachyonic fields will enter the mainstream and become as widely known as QM today. But WP is not a crystal ball, and we can only base decisions on usage now, which clearly indicates that "Tachyon" as the FTL particle is the primary topic.--JohnBlackburne^words_deeds 01:43, 14 February 2012 (UTC)

By that logic, the long-term significance criterion given at WP:PRIMARYTOPIC can never be applied, only the usage criterion can be used. As such, you are advocating a significant change to wiki's existing policies and should be discussing that on the relevant page, rather than disputing this particular application of them. Waleswatcher (talk) 01:56, 14 February 2012 (UTC)

"Maybe tomorrow someone will discover real tachyons" FYI, the combined data from ATLAS and CMS at the LHC is nearly at 5-sigma for a Higgs discovery. Translated into English, that means that someone (or rather a few thousand someones) almost certainly has discovered a tachyon - a tachyonic field, that is. The Higgs boson is an integral part of the Standard model of particle physics, and according to the standard model it had a tachyonic mass term in its uncondensed phase in the early universe, before it condensed into the current (stable, hopefully) phase. That tachyon condensate is what generates Mass for fundamental particles and breaks electroweak symmetry. Someone should add some of that material to the Tachyonic field article, since I think most people would agree it's quite interesting - but I'm rather unmotivated to do so at the moment, given that hardly anyone is every going to read it with the current insistence on hiding it. Waleswatcher (talk) 02:11, 14 February 2012 (UTC)

There is no "we", there is only one person that has a problem. The article is only about one meaning. All articles are about one meaning. WP is not a dictionary Bhny (talk) 23:32, 13 February 2012 (UTC)

Then I suppose you'll be deleting the material about Feinberg (the author of the paper that coined the term "tachyon") from this article, Bhny? After all, his article is about fields with imaginary mass. While you're at it, most of the other references should be expunged as well. Have at it! Waleswatcher (talk) 23:39, 13 February 2012 (UTC)

Fair warning: later today when I have time I'm going to make some edits to the article. I'll try to make them one at a time, so please object to (or revert if you must) only the ones you can't abide by. I'll start with the least controversial - the lead is a mess, it shouldn't mention "spacelike four-momentum" in the opening paragraph. Another issue is that the paragraph that mentions quantum fields with imaginary mass - the paragraph that's in the article now, mind you, the one that refers to Feinberg etc. - is a little too terse, because it doesn't mention why quantum fields have anything to do with this, or why imaginary mass might have confused those early authors. Before all my edits were blanket reverted, I had fixed some of those problems. Waleswatcher (talk) 12:34, 14 February 2012 (UTC)

Two changes made, more to come. I'll pause for a while in case anyone has objections. Waleswatcher (talk) 15:34, 14 February 2012 (UTC)

OK, done for now. Some new material added including new sources, significant re-arrangement of the lead, and clarification of the origin of the name and the underlying physics. Please discuss here before reverting. Thanks. Waleswatcher (talk) 16:54, 14 February 2012 (UTC)

Lead sentence and hatnote

Per WP:LEAD and in particular WP:BOLDTITLE the article should begin with a statement of the topic, which is "tachyon", I.e.

A tachyon is....

It is not a 'tachyonic particle'. That was resolved in this thread, it seemed to all our satisfactions, so that 'alternate title' should not be introduced in such a way because one editor disagrees with that consensus.

As for dismbiguation now there's a disambiguation page there should be a link to it, to collect together the more than a dozen different uses for the word. There's no need to highlight one of them, especially not one on a relatively obscure topic, going by stats, that Wikipedia has managed for almost ten years with anyone creating a topic on tachyonic fields, and that's mentioned in the lead in context.

A third opinion on both these issues would be appreciated.--JohnBlackburne^words_deeds 01:09, 15 February 2012 (UTC)

There is and was no such consensus, and there is a clear and obvious need to highlight the only other usage that could possibly be confused with this one - especially considering that it is actually primary. Even if it weren't, it goes by exactly the same name in (literally) thousands of reliable sources, and as such is much more likely to be confused than any of the other usages. The example of Inflation (among many others) shows that such a hatnote is quite standard.

Above, I've posted evidence of approximately 9,000 reliable sources using "tachyon" to mean a field with imaginary mass. Those who believe tachyon as an FTL particle is the primary usage have posted a grand total of 1 reliable source (Tipler). Both by usage and by enduring educational value, Tachyonic field is the primary article. Waleswatcher (talk) 05:34, 15 February 2012 (UTC)

Now the move discussion is concluded I hope we can come to some consensus on this. Again per WP:LEAD as the topic is "Tachyon" that should appear as early as possible in the first sentence, so it should begin "A tachyon...". If "tachyonic particle" is an alternative common name then that should be mentioned but I see little evidence of that: per the move discussion the particle is universally referred to as a "tachyon". "tachyonic particle" looks like a derived term much like one might refer to the "American nation" rather than "America", or a "British person" rather than a "Briton".

As for the hatnote I don't see why out of all the possible uses for "tachyon" this one should be highlighted in the hatnote. If it were a major alternative use maybe, but other uses are far more common both based on their article or based on a google search. This could change, as we now have an article for tachyonic field it could become more popular, so much so that it needs a direct link in the hatnote, in addition to the one in the lead. But I don't see that this is necessary now. --JohnBlackburne^words_deeds 16:45, 19 February 2012 (UTC)

Mentioning tachyonic field in the hatnote is not doing much harm. Tachyonic fields are common enough in the technical literature to warrant a direct link. It is a topic, that advanced undergrads/ grad students are not unlikely to look for under the term tachyon. If they end up at this article, without the direct hatnote they mat (wrongly) conclude that wikipedia does not cover the use (because it is too technical or something). TR 17:39, 19 February 2012 (UTC)

That is true of many other things though: for some people the Tachyon XC camera or the Tachyon: The Fringe game will be what they are looking for and expect to find here. Because we can't include them all in the hatnote it's normal to include none, unless one is especially common. And the discussion above seemed to resolve that - even in physics 'tachyon' almost always means the FTL particle.--JohnBlackburne^words_deeds 17:52, 19 February 2012 (UTC)

I'm going to follow through on the alternative course of action discussed above and put much of the tachyon field material back in, following Timothy's suggestion of using a template. After that, this particular discussion may become moot. Waleswatcher (talk) 17:43, 19 February 2012 (UTC)

The article is about the particle

Again, and per the just concluded move discussion, this article is about the hypothetical FTL particle. I have restored the lead to the version prior to this revision which totally changed the sense of what the article is about.--JohnBlackburne^words_deeds 18:27, 19 February 2012 (UTC)

That was not discussed at the move discussion. What was discussed at the move discussion was whether or not to move the name. Moreover, the change you reverted didn't add any new material - it simply moved some sentences that were down a paragraph or two into the lead paragraph. And in addition, your revert undid a bunch of other typographical and wording changes that benefited the lead. Please try to edit constructively. Reverted. Waleswatcher (talk) 18:38, 19 February 2012 (UTC)

It was precisely what the move discussion was about. This article is on the FTL particle. It was proposed to move it to tachyon (particle). That proposal failed, but it does not change the content of the article. "Tachyon" is still the common name for the FTL particle, and that is what the article is about. You should not now try to re-write the article against the consensus established in the move discussion.--JohnBlackburne^words_deeds 18:45, 19 February 2012 (UTC)

And the reason for restoring the lead is it was the only way to get back to the version matching the RM discussion; it was the first change you made but I could not undo that one change, and you made so many changes after in rapid succession that I could not unpick them.--JohnBlackburne^words_deeds 18:54, 19 February 2012 (UTC)

Again - the discussion was on a proposed move of the name. That discussion concluded with a majority against the move. During the course of that discussion, it emerged that fields of imaginary mass are referred to as "particles" in several reliable sources. This was one of the reasons given to oppose the move.

Regarding the content of the lead, the edit you are objecting to did not add any significant new content. It simply re-arranged material that was already in the lead so that it more accurately introduces the topic and summarizes the article, not to mention starting the first sentence with tachyon as you requested. As for the body of the article, several of the people opposed to the move supported the idea that this article discuss such topics as the tachyon of bosonic string theory. Waleswatcher (talk) 18:56, 19 February 2012 (UTC)

Let also remind you that as of a few weeks ago there was only a single article, titled "Tachyon", which discussed both the FTL particle and imaginary mass fields. If anyone doesn't agree that the current article is a vast improvement, their work is cut out for them. Waleswatcher (talk) 19:20, 19 February 2012 (UTC)

It's clear there is no point discussing with you as after multiple discussions on this talk page which have resulted in clear consensuses that this article is about the particle you keep rewriting the article to say something completely different. Please stop.--JohnBlackburne^words_deeds 22:00, 19 February 2012 (UTC)

I'm sorry you feel that way. Wikipedia works by seeking a consensus when editors disagree. If you are both unwilling to discuss changes here and simply revert them rather than editing constructively, that makes consensus impossible to achieve (and violates wiki's policies). One option you might consider is starting a Wikipedia:Mediation Cabal case, but I'm not sure it's necessary. For my part, I'm happy to discuss the article with you (or anyone else). Waleswatcher (talk) 22:12, 19 February 2012 (UTC)

We have had the discussions here and here. In both the consensus was that this article is about the FTL particle. Im sorry if these two discussions have not convinced you, but the proper thing to do is to admit you've failed to convince others and move on. You should not now be editing the article in line with your views against this clear consensus.--JohnBlackburne^words_deeds 22:21, 19 February 2012 (UTC)

I'm not even sure what your position is. You seem to think only the "particle" meaning of tachyon should be discussed in this article, but you haven't explained why you think that or even what you mean by it (nor was there any such consensus in any of the above discussions). For instance, when Brain Greene refers to the lowest mode of the bosonic string as a "tachyon" and as a "particle", is that material permissible in this article according to you? What about Lisa Randall? If it is permissible, what are you objecting to? If not, why not? What about Feinberg's 1967 article - the one that coined the term "tachyon"? Is discussion of that article permissible? If so, how can one possibly avoid mentioning fields with imaginary mass, when that's the topic of much of that paper? Waleswatcher (talk) 22:40, 19 February 2012 (UTC)

Everyone's position is this article is about the FTL particle. Even your position is that this article is about the FTL particle. The first sentence should say that a tachyon is a FTL particle and the disambig goes in the hatnote. (as I've said before) Bhny (talk) 22:45, 19 February 2012 (UTC)

"Even your position is that this article is about the FTL particle." Ummm... what? No, it isn't.

WE have 2 articles about 2 different definitions. What on earth do you think this article is about? Bhny (talk) 01:15, 20 February 2012 (UTC)

"What on earth do you think this article is about?" Tachyons.

Which definition of Tachyons is this article about? It is about the FTL Tachyon. You really are trying hard to not understand us. I'm finished with this page. Please don't ask me any more questions.Bhny (talk) 13:45, 20 February 2012 (UTC)

It's about the definition of "tachyon" as it's used in reliable sources, both technical and popular. That includes both the FTL particle and the imaginary mass field meaning. This article should discuss both, and in particular it should include a clear description of the fields, why they are relevant, why they are also called tachyons, etc.

No, that's not how Wikipedia works. For example the name Macedonia is used for two distinct geographic entities, the former Yugoslav republic and the part of Greece. Both are called 'Macedonia', but they are separate articles, not one article discussing both meanings. In that case there's a disambiguation page to mediate between them, but if one of them were clearly primary it would be at "Macedonia".

As there here. It is one article per topic, and this article is on the FTL particle, not on anything else. Other topics should have their own articles, linked from the disambiguation page and from here if they are related. We resolved the matter of this article's name above, so "Tachyon" is the correct name for this article. This may change one day but for now it's the clear primary topic.--JohnBlackburne^words_deeds 19:57, 20 February 2012 (UTC)

This discussion would be easier to follow if people would refrain from inserting comments in the middle of someone else's. Thanks. Regarding your comment, that's your opinion, but it's not consensus (as the recent edit history makes quite clear, not to mention what came before). The fact is that these two meanings are tightly connected: by their common origin in Feinberg's paper, by the physics, and by the common and technical usage. It seems that we are heading for an article that focuses on the FTL particle, but that discusses imaginary mass (both for particles and fields) at some length and refers to the tachyonic field article for further details. At the moment, the main disagreement seems to be over where in the lead to first mention Feinberg and negative mass fields, not whether to. Waleswatcher (talk) 20:12, 20 February 2012 (UTC)

As for being finished, as you wish - but be aware that if you refuse to answer reasonable questions about content or discuss the article on the talk page, you're not going to be able to help achieve a consensus (which obviously does not exist, as recent edits emphasize). Waleswatcher (talk) 14:38, 20 February 2012 (UTC)

Now, are you going to answer the questions I asked you? Waleswatcher (talk) 01:26, 20 February 2012 (UTC)

If your questions are like the one below about sources then: no, that was the move discussion that is now closed. You've had your week of people reading your unconvincing arguments, no-one now is interested in re-opening that debate. It is closed, move on.--JohnBlackburne^words_deeds 01:35, 20 February 2012 (UTC)

Are you going to answer those questions, John? Waleswatcher (talk) 02:17, 20 February 2012 (UTC)

Let me ask you the same questions I asked John: when Brain Greene refers to the lowest mode of the bosonic string as a "tachyon" and as a "particle", is that material permissible in this article according to you? What about Lisa Randall? If it is permissible, what are you objecting to? If not, why not? What about Feinberg's 1967 article - the one that coined the term "tachyon"? Is discussion of that article permissible? If so, how can one possibly avoid mentioning fields with imaginary mass, when that's the topic of much of that paper? Waleswatcher (talk) 23:01, 19 February 2012 (UTC)

Michael C Price's edits

His first edit removed a sentence added by TimothyRias and some other material he last edited. Contrary to the edit summary, it did not remove the material on fields with imaginary mass - it just removed the most important and relevant part of it, the part that pointed out that such fields do not correspond to FTL particles. It also broke a citation.

As for the material on the "Feinberg reinterpretation principle", it is sourced only by a paper (Feinberg 1967) that is known to be wrong. Unless notability can be established, by WP:RSUW it should be removed. Waleswatcher (talk) 23:41, 19 February 2012 (UTC)

Looking at the abstract of the paper which is claimed to "disprove" Feinberg, I don't see anything which refutes Feinberg. It says that there are non-FTL modes of transmission, but not that all modes are non-FTL.-- cheers, Michael C. Price ^talk 08:52, 20 February 2012 (UTC)

Actually, if you read the article you will notice that it says all modes of field of the type that Feinberg described propagate subluminal (note that Feinberg already notes in his article that a more careful analysis of the actual propagation speed is needed). The non causal modes only occur in certain singular models (as is noted even in the abstract).TR 09:22, 20 February 2012 (UTC)

"Singular" is described as meaning "in the sense that there does not exist a unique one-to-one relationship between the momenta and the velocities." Is there a free link to the full article anywhere? -- cheers, Michael C. Price ^talk 10:15, 20 February 2012 (UTC)

That article shows that the signal velocity - that is, the maximum propagation speed of any signal - of a Lorentz invariant field theory with canonical kinetic term and negative mass squared is c, regardless of the sign of the mass squared term. If you know something about hyperbolic partial differential equations, that's because the characteristics - the "light cone" - have nothing to do with the mass term at all. They are determined by the terms in the equation of motion with derivatives; specifically, by the terms with the highest numbers of space and time derivatives. The "singular" in the abstract is referring to what happens if you try to make a field that really does propagate FTL - you have to modify the kinetic term (not the mass), and in doing so you make the equation higher than 2nd order, which introduces various pathological extra solutions (usually known as "ghosts" these days). This is all completely standard stuff by now, but as far as I know the Susskind et al article in 1969 was the first to show it.

If that explanation doesn't make sense to you, please search for "pendulum" on this page and try that one. Lastly, here's a quote from Lisa Randall: "People initially thought of tachyons as particles travelling faster than the speed of light...But we now know that a tachyon indicates an instability in a theory that contains it. Regrettably for science fiction fans, tachyons are not real physical particles that appear in nature." Waleswatcher (talk) 11:29, 20 February 2012 (UTC)

Well, I would like to read the article to check that it really does say that and that there is no OR here. (I accept that signal propagation is limited by c, but that is not the same as particle velocity = group velocity = field propagation velocity.)-- cheers, Michael C. Price ^talk 13:37, 20 February 2012 (UTC)

Hi Michael, please go ahead and read it - or see the quote by Randall, or read any of the thousands of other scientific articles on tachyons, all of which agree on this point. FYI, the group velocity for a negative mass squared field is indeed superluminal, that's what misled Feinberg in the first place. But the modes of the field have imaginary frequency for momentum<mass, as you can immediately see from the dispersion relation. That simply means that the field configuration is unstable (the pendula want to fall over). If you make a localized perturbation (like a delta function) at time t=0, its effects spread out at speed c and are confined to the future lightcone. Moreover, its effects grow exponentially inside that lightcone. In general, there are no localized oscillations that can be interpreted as individual particles - the exponential growth is the instability to tachyon condensation (in a sense, it's the spotaneous, runaway creation of lots and lots of tachyon particles - but none of them can go FTL). Mathematically, as you may know it's not the group velocity that determines the maximum speed of signal propagation, it's the phase velocity at infinite frequency - which is c. Waleswatcher (talk) 14:42, 20 February 2012 (UTC)

A kind soul has sent me the article. I shall to digest it more fully later, but two immediate thoughts: first, they do not reference or address Feinberg, so we should be careful about saying that it refutes Feinberg reinterpretation. Second, they conclude "We conclude that whenever truly noncausal behavior occurs, it is linked to a peculiarity in the equation of motion such that the solution at later times is not always determined by initial data." But isn't this just a restatement of acausality, which we might expect with tachyons? -- cheers, Michael C. Price ^talk 16:20, 20 February 2012 (UTC)

On the first point, I think we just need to word it so as not to overstate what Feinberg said about superluminal propagation (after all, he does say that the issue needs more study, or something to that effect). On the second, they're referring to the fact that to get superluminal propagation you need to modify the kinetic term (i.e. the terms with derivatives in the equation of motion, as opposed to the potential energy terms like the mass) in a certain way that also introduces a pathology in the Cauchy problem. In retrospect you're right that's it's vaguely obvious that something like that should be true (kill your own grandfather etc.) - but the take home point for us is that fields with negative mass squared and canonical kinetic terms, aka tachyons, do not propagate superluminally under any circumstances. Waleswatcher (talk) 19:27, 20 February 2012 (UTC)

Order of paragraphs in the lead

I think the paragraph on Feinberg should come high up in the lead. Feinberg coined the term, was the first to study the relativistic kinematics of FTL particles, was the first to study imaginary mass fields, was the first to propose that they might propagate FTL, and created the semantic issue that is causing all these issues.

By contrast, the Sommerfeld reference - which I moved below Feinberg - is a paper from 1904. That's before special relativity, so it's from before the time that the speed of light was thought to be any kind of barrier. While I haven't read it (I'm the one that added that reference by the way, but didn't yet get access to the paper), it can't possibly contain any of the material in the article, because the material in the article more or less all relies on relativistic kinematics. So it's quite peripheral, and probably shouldn't be in the lead at all - it's a historical side note at best. Waleswatcher (talk) 15:11, 21 February 2012 (UTC)

History

Good call on adding the History section. I was just thinking about doing that myself. It is a good place for some of the stuff that was in the lead but was rather misplaced (also per WP:LEAD the lead should not contain material (beyond some basic stuff like alternate terms/pronunciation/etc.) not contained in the main body.) Some issues: (although not the highest priority)

• We need a proper source for the claim that the first hypothesis on FTL particles is attributed to Sommerfeld, i.e. we need a source that actually attributes this to Sommerfeld. (Note that this is one of those things where the citation requirements differ from what you would usually do in scientific papers. For people with a background in scientific writing this can need some getting used to.) (Second note (not about the history section) there is a similar problem with the citations for the claim the term tachyon is often used for imaginary mass fields. Giving (many) citations of examples of use is not enough (in fact it is a form of WP:OR), instead we need a (reliable) source that actually comes out and says that it is often used for this. This can be quite bothersome for this type of statements because such sources rarely exist. For this reason it can be better to just state that it is used this way and avoid the issue.
• The section can use some more detail (e.g. on the type of work done before Feinberg). Of course sources may again be a problem. But one thing could be a discussion of the type of (classical) objections to FTL particles that Feinberg discusses in the first part of his paper (and dismisses).

TR 17:32, 21 February 2012 (UTC)

• The Sommerfeld thing with more or less that wording was in the old article, without a reference. I added that Sommerfeld cite based on its title, but I will try to get a hold of a copy and make sure it's the right one. Maybe to avoid the problem with saying it's the earliest we can instead say "an early hypothesis" or something like that?

  Regarding "often", can we perhaps change it to "many"? Considering that the Sen paper has 720 citations, that seems fairly solid, no?

  I completely agree we could use more detail in the history section. By the way regarding the title of Feinberg's paper, I just thought it made sense to include it to make clear what his goal in the paper was. But I don't think it's a big deal either way. Waleswatcher (talk) 18:41, 21 February 2012 (UTC)

Notability/due weight and the "Feinberg reinterpretation principle" section

The material on the "Feinberg reinterpretation principle" is sourced only by a paper (Feinberg 1967) that is known to be wrong in at least some crucial respects. Unless notability and due weight can be established, by WP:RSUW this section should probably be removed. Does anyone have any sources that show that the reinterpretation principle is taken seriously by scientists? Waleswatcher (talk) 17:17, 27 February 2012 (UTC)

The term "Feinberg reinterpretation principle" seems rather rare (I find only 3 books that even mention the term. And these are not to most notable at that). However, if you look for "reinterpretation principle"+tachyon you will actually find a bunch. Similarly, there is a bunch of aritlce on gscholar which do discuss this notion. So clearly, the notion can be sourced from other sources as well.

Poking around in the sources, it appears that the principle was proposed by Bilaniuk, Deshpande, and Sudarshan 1962.TR 17:55, 27 February 2012 (UTC)

Interesting - so it may not be the "Feinberg" reinterpretation principle after all? That should get sorted out, and then there remains the issue of whether devoting that much space to it is in accord with WP:RSUW. I think we should try to find some recent sources, since the understanding and interpretation of all of this has changed dramatically since the 1960's. Waleswatcher (talk) 20:20, 27 February 2012 (UTC)

I agree, more recent sources should lead to a better coverage of the subject.TR 21:25, 27 February 2012 (UTC)

Reading one of the sources your google link brought me, the author first demolishes the idea that the "reinterpretation principle" can avoid causal paradoxes with several examples (mainly due to Benford, Book, and Newcomb), and then attributes a very different view to Bilaniuk and Sudarshan. He says that they "in the end opt for" the idea that the relativity of simultaneity is simply invalid, because there is a preferred reference frame that establishes causality (and so tachyons never go back in time). In my own opinion that's the only sensible route, and it's discussed in passing in the article. If that source is accurate, I think we should delete this section, or at best mention that its own proponents abandoned it in favor of Lorentz violation. Waleswatcher (talk) 20:30, 27 February 2012 (UTC)

Few if any recent sources attest to the notability of this section, and instead it seems that this principle is (1) not originally due to Feinberg, (2) known to fail at its intended purpose (see Tachyonic antitelephone), and (3) was abandoned by its original authors. As such, I'm going to delete it unless there are objections. Waleswatcher (talk) 12:54, 1 March 2012 (UTC)

The source cited does not demolish[..] the idea that the "reinterpretation principle" can avoid causal paradoxes, it merely expresses incredulity and a misunderstanding of the relevance of spontaneous emission. I also note that they quote the longest passage from Feinberg (who mentions the spontaneous emission issue, unlike Bilaniuk and Sudarshan) and merely snatches of sentences from Bilaniuk and Sudarshan.

I interpret the claim that Bilaniuk and Sudarshan opt to reject the reinterpretation principle as evidence that (1) they diddidn't originate the same concept as Feinberg (2) their concept was inferior to Feinberg's.

-- cheers, Michael C. Price ^talk 14:26, 1 March 2012 (UTC)

It does demolish it, with specific examples and some extensive arguments - you just think it's wrong (which is fine, you're entitled to your opinion). But we need to establish notability here, and that source at least undermines it pretty thoroughly. Do you have any other sources besides Feinberg? Waleswatcher (talk) 00:59, 2 March 2012 (UTC)

It's a side issue, as noted below, but give me the page numbers where the specific counter examples are. -- cheers, Michael C. Price ^talk 16:34, 2 March 2012 (UTC)

Pages 123-128 are more or less entirely devoted to that. Waleswatcher (talk) 18:42, 3 March 2012 (UTC)

And they repeatedly make the same simplistic error, viz detecting a tachyon from the future does not imply that someone sent it, hence no information is carried back in time; that is the crux of their error. Priming the detector simply emits the tachyon forward in time. As the article says, emission and absorption processes can't be distinguished for FTL particles since they can be Lorentz rotated into each other - physically they are the same. -- cheers, Michael C. Price ^talk 23:12, 3 March 2012 (UTC)

I understand that's what you think. I think you're wrong (and FYI that source explains in detail and at length why not being able to distinguish emission and absorption does not resolve the paradox). But our opinions aren't what's at issue here. It's clear now that the section is mis-titled (see here, where Feinberg is not even mentioned) and, more importantly, that the principle is not widely accepted (even the "no-paradox" review TR posted below states that). Instead, the prevailing view seems to be that FTL is consistent only if Lorentz invariance is broken in a way that preserves time-ordering even with FTL particles. I think there's more than enough sources now to re-write it along those lines. Waleswatcher (talk) 23:47, 3 March 2012 (UTC)

The source does not "explain[..] in detail and at length why not being able to distinguish emission and absorption does not resolve the paradox" - it fails to understand Feinberg completely. Where they say, for example that the direction of information flow is a Lorentz invariant, they are completely correct, but they have failed to grasp the fact that there is no information flow at all. All so-called detection events are actually instances of local spontaneous emission, and local spontaneous emission doesn't convey information from anywhere else. -- cheers, Michael C. Price ^talk 17:27, 4 March 2012 (UTC)

Again, it's fine for you to hold that opinion, but your opinion (and mine) aren't particularly relevant. You need to produce reliable sources that say that this principle is notable and taken seriously today. I've done quite a lot of work finding sources that mention it, and they all agree that it is not widely accepted, indicate that it is not even due to Feinberg, and they are nearly unanimous that FTL particles in Lorentz invariant theories lead to paradoxes. As such, we can't devote a lot of space to it. By WP:NPOV we can perhaps briefly mention it, while at the same time explaining why it isn't accepted and the arguments against it. Waleswatcher (talk) 19:17, 4 March 2012 (UTC)

It is not an opinion that Feinberg mentions the key concept of spontaneous emission. Do Bilaniuk and Sudarshan mention this? -- cheers, Michael C. Price ^talk 21:06, 4 March 2012 (UTC)

Note that the correctness of the principle is irrelevant to it notability. All we need is discussed in secondary sources. It appears that there was significant discussion on the issue whether the principle did or did not solve the causal paradoxes implied by tachyonic particles. (See for many sources this google scholar search.) The principle seems notable enough to discuss in this article. What we need for proper NPOV treatment are a couple of recent secondary or tertiary sources that establish what the scientific consensus on the conclusion of this debate is.TR 12:33, 2 March 2012 (UTC)

Fair enough - you're right that being wrong doesn't make something not notable, but we still need to establish due weight. Anyway, I wouldn't object to the article discussing it after a rewrite that accurately describes the origin of this idea and the current consensus on it. If we can't locate reliable, recent sources describing said consensus/debate, then I think that's a sign it's not notable after all and it should be deleted. So - I'll wait a while for such sources to be added, but if none show up, I'm going to remove it. It can always be added again in the future if sources are found. Waleswatcher (talk) 12:49, 2 March 2012 (UTC)

Here at least is a relatively recent (published in 2000) article reviewing the discussion that claims that the reinterpretation principle does solve causality paradoxes.TR 15:40, 2 March 2012 (UTC)

Looking through the most recent sources, it seems that a clear consensus was never really reached. Some proponents of the reinterpretation principle (like Recami) maintain that causality paradoxes can be solved by the RP, while this is denied by others. Either way, there is a fair amount of journal articles in respectable journals that discuss this issue.TR 16:11, 2 March 2012 (UTC)

In fact, the abstract of that paper states "it is possible ...to solve also the known causal paradoxes, although this is not widely recognized yet." So, according to that source, it is not widely recognized that these paradoxes can be solved (or wasn't in 2000 at least). I think that's a significant understatement. Given that this paper claims to "solve" these fundamental paradoxes, the fact that it was published in a relatively obscure journal and only has 24 citations 12 years later - and a significant fraction of those are in later papers written by its authors - doesn't speak highly of its reliability. A more reliable review, slightly more recent, is here. It endorses precisely the view that I think is widely accepted - that FTL is OK only if there is a preferred frame (ie. of Lorentz invariance is broken):

"Obviously, there can be no paradox if, in one particular reference frame, tachyons can only propagate forward in time. Of course such a restriction is anathema in the standard approach to special relativity since it picks out a preferred frame. However if you have good physical reasons for picking out a preferred frame... [in conclusions] ...do not lead to causal paradoxes, which can arise only from tachyons whose speed has no fixed value in a given reference frame."

In other words, if tachyons obey the Lorentz covariant kinematical equations given in this article, which allow them to go any FTL speed in any reference frame, you've got paradoxes. In cases where there's a preferred frame, maybe not. Waleswatcher (talk) 18:57, 3 March 2012 (UTC)

Some notes:

1. That source does not discuss the reinterpretation principle at all. In fact, it explicitly states that it won't discuss proposals of that type.
2. The statement you quote, simply says that if there is a preferred frame of motion (such as in the Scharnhorst effect which is what that article is mainly about) then causality problems can be resolved. This says nothing at all about whether causality paradoxes can be resolved in the absence of such a preferred frame.TR 11:53, 4 March 2012 (UTC)

That's all correct as far as it goes, but there's more to it than that.

• That paper is a review of sorts of FTL propagation and causality, as its abstract says. And yet, it never even mentions the reinterpretation principle, and instead focuses entirely on Lorentz breaking situations. Why? Clearly because the authors don't think it's worth discussing.
• And as I pointed out above, even the review you posted says that it is not widely accepted that these paradoxes can be resolved, and then claims to solve them itself (but said "solution" has been essentially ignored since). So at the moment, we still have zero recent reliable sources that indicate that this is widely believed or taken seriously as possibility.
• Looking around some more, here's a 2010 paper titled "On the impossibility of superluminal travel: the warp drive lesson". it's focused on general relativity and the physics that prevents you from exceeding c there, but again, no mention of the "reinterpretation principle", and a clear statement that FTL leads to paradoxes: "As a matter of fact, any mechanism for superluminal travel can be easily turned into a time machine and hence lead to the typical causality paradoxes associated with these mind-boggling solutions of GR."
• Here's another recent paper, this one concerned with an exotic model that allows superluminal propagation in certain (Lorentz violating) backgrounds. A sentence from the conclusion: "This is why the causal paradoxes arising in the presence of tachyons^5 (superluminal particles in the Minkowski vacuum) do not appear here." [footnote 5 states: "Do not confuse them with field theoretical tachyons with m^2 < 0." - so you see that even authors of scientific papers about superluminal propagation are careful to disambiguate the two.] Waleswatcher (talk) 15:04, 4 March 2012 (UTC)
• One more, this one with nearly 200 citations despite being from 2006: "All of our considerations in this paper have concerned Lorentz-invariant theories...the presence of the asymptotic Minkowski space that allows us to get into paradoxes...our arguments do not directly apply to theories in which the vacuum spontaneously breaks Lorentz invariance". The conclusion of that paper is actually even stronger than the others, it argues that no non-paradoxical theory can exhibit superluminality even locally in non-vacuum states. No mention of "reinterpretation" in any of the above. Waleswatcher (talk) 15:11, 4 March 2012 (UTC)

Michael C Price's latest edits to Feinberg reinterpretation principle

I'm starting a new section on this for clarity. The latest edits are not acceptable to me, and violate WP:NPOV. Among other changes, Michael's edits have changed the date on the "better sources needed" tag. His justification is that Feinberg is the reference for Feinberg's principle, which is absurd. Feinberg was already referenced when I added that tag, the whole point is that we need other sources.

The research that TR and I have done has uncovered several references that discuss a "reinterpretation principle" in the context of tachyons. Almost none refer to it as the "Feinberg reinterpretation principle". For example, this paper reviews the history of tachyon paradoxes in this paragraph:

Claims exist since long that all the ordinary causal paradoxes proposed for tachyons can be solved[27, 28, 29] (at least “in microphysics”) on the basis of the “switching procedure” (swp) introduced by St¨uckelberg[30], Feynman[30], Sudarshan[27], and Recami et al.[26, 28], also known as the reinterpretation principle: a principle which in refs.[26, 28] has been given the status of a fundamental postulate of special relativity, both for bradyons [slowerthan-light particles] and for tachyons. Schwartz,[31] at last, gave the swp a formalization in which it becomes “automatic”

None of those references are to Feinberg.

So there are two possibilities

• (1) there are two different reinterpretation principles for tachyons. If so, by WP:NPOV the non-Feinberg principle needs more space than the Feinberg principle, because more reliable sources discuss it, and there are many more sources for it (see the references in the paragraph quoted above). Given that neither principle is very well-supported, this other reinterpretation principle shouldn't get much more than a brief paragraph. In any case, the section needs to be re-written.
• (2) The two are the same (I think this is the case, or close enough). If so, the section is mis-titled, needs more sources, and needs to be re-written.

Since Michael has engaged in an edit war, I will wait for a little while to let things cool off, but then I will edit.Waleswatcher (talk) 15:48, 5 March 2012 (UTC)

To say that I'm engaging in an edit war when I restored the entire section that WW deleted is absurd. I have added and expanded the explanation of the FRP, sourced from Feinberg's article, since it was evidently misunderstood by WW and others.

As for the question of whether there is more than one RP, that is a grey area. Feinberg and Bilaniuk_&_Sudarshan came up with the basic idea of negative energy particles travelling back in time are positive energy particles travelling forward independently, but Feinberg's conception was more developed, since he saw the link between detection and spontaneous emission, which seems lacking in B&S's account. Hence B&S abandoned their half-idea. Most of the "refutations" of the RP have demolished B&S's incomplete conception and have not addressed Feinberg's more complete reinterpretation principle. -- cheers, Michael C. Price ^talk 16:26, 5 March 2012 (UTC)

Feel free to provide reliable sources that support your assertions. Until then, the material you have added to the article is in violation of wikipedia's policies. Waleswatcher (talk) 17:35, 5 March 2012 (UTC)

Your refusal, once again, to address the earlier techical issues is noted. As for whether my contributions to the article are in violation with wikipedia's policies, your opinions are noted; needless to say, I disagree with your opinions. Encyclopedias exist to inform people; explaining Feinberg's reinterpretation principle is informative to readers trying to find out about tachyons. If you want to explain that in the context of other people's attempt to formulate tachyon reinterpretation principles, I have no problem with that. But deleting the entire section is not useful.

-- cheers, Michael C. Price ^talk 18:49, 5 March 2012 (UTC)

I haven't been addressing the "technical" issues because original research is not permitted on wikipedia, and that is what you are engaging in. Discussing it does no good - until you provide reliable sources, your material is in violation of wiki's policies, regardless of its correctness. I will say, however, that not being able to distinguish emission from absorption fails to resolve the paradoxes (as the "logically pernicious self-inhibitor" shows). Instead, what it required is that tachyons cannot be controlled at all. In other words, you cannot build a machine that can produce/absorb tachyons when you want it to. If so, you might be able to avoid these paradoxes, but that means that tachyons are nothing like ordinary particles with interactions and laws of physics that can be understood and made use of. Waleswatcher (talk) 16:37, 6 March 2012 (UTC)

You still don't get it, do you? Not being about to distinguish (spontaneous) emission from absorption is what leads to the tachyon's uncontrollability. Guess that explains why you deleted this from from the article. -- cheers, Michael C. Price ^talk 18:25, 6 March 2012 (UTC)

No, those are not the same thing. Suppose I have a switch on my device that if I flip it to ON, my device will emit or absorb tachyons (I can't tell which is which), but if it's OFF, it neither emits nor absorbs tachyons. Such a device leads directly to a paradox. Waleswatcher (talk) 04:41, 7 March 2012 (UTC)

No it doesn't - for the reasons which you've deleted from the article. -- cheers, Michael C. Price ^talk 06:15, 7 March 2012 (UTC)

Yes, it does - for the reasons discussed extensively in several of the scholarly sources cited in the article. But I'm glad you've now understood that these two criteria are not the same. I recommend you read this - it's short and very clear (and written several years after Feinberg, which it references in a rather dismissive way). Waleswatcher (talk) 06:44, 7 March 2012 (UTC)

Yes, they make the obvious point - which we've already discussed - that the direction of information flow is invariant. But of course, you didn't hear the answer, which is that there is no information flow. (See their 2nd sentence, 4th paragraph.) -- cheers, Michael C. Price ^talk 07:58, 7 March 2012 (UTC)

Did you read anything past that sentence, Michael? To avoid having information flow, you cannot be allowed to in any way modulate the tachyon beam. You cannot in any way control whether tachyons are emitted or received (it makes no difference which it is, or whether you can tell which it is). But that's impossible unless tachyons don't interact with anything. And if they don't interact with anything, they don't exist. Waleswatcher (talk) 08:12, 7 March 2012 (UTC)

Correct up to "But that's impossible unless tachyons don't interact with anything." The whole point of Feinberg's article is that interaction without signalling is possible. -- cheers, Michael C. Price ^talk 08:23, 7 March 2012 (UTC)

And the whole point of this article (and multiple others) is that it's not possible. Feinberg was wrong (and not just about that, as you know). If tachyons interact with anything, your actions can affect them. If your actions can affect them, you can create anti-telephones and logically pernicious self-inhibitors (that name is so good I'm tempted to add it to the article). Waleswatcher (talk) 08:50, 7 March 2012 (UTC)

No, Feinberg was right, because (assuming tachyons exist and interact) every time you try to detect a tachyon you actually emit one, hence you always record a "hit". Hence no information. Your counter arguments are just a mess of unexamined assumptions. -- cheers, Michael C. Price ^talk 08:58, 7 March 2012 (UTC)

For the third time, it makes no difference whether you are detecting or emitting - it matters only whether you can affect them. That's the conclusion of the paper I linked you to, as well as many others. In any case, as I said before this conversation is a waste of time and inappropriate for a talk page. Wikipedia requires reliable sources, and it requires NPOV. The original research and personal opinions of editors aren't relevant. I will not respond to any more of your comments on this issue. Bye. Waleswatcher (talk) 09:04, 7 March 2012 (UTC)

You're right, there's no point continuing this - you obviously don't understand the subject and never will. So much for being a self-declared tachyon expert! What a joke. You need to examine what you mean by "affect" (which comes down to absorption and emission, of course.)-- cheers, Michael C. Price ^talk 09:09, 7 March 2012 (UTC)