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Archive 1 | Archive 2 | Archive 3 |
Tachyons arise in many versions of string theory.
Could tachyons be gravitons?
I think it appear only in the bosonic string theory?? no? -- Pascal Gauthier 09:22, 14 Mar 2007 (UTC)
Does anyone want to clarify this sentence? It is very confusing with the double negatives.
Tachyons is theorized to exist in universes with extra time dimensions. A universe with 1 space dimension and 3 time dimensions are comprised of only Tachyons.
Could anyone add a link to the name for particles at sub-luminal speeds? I forgot what the name was. -- Redge 11:54, 13 Jun 2004 (UTC)
Can anyone verify this? I removed it as it sounds highly dubious to me; in any case, it is too vague.
We might also need discussion about the wave front effect, virtual particles, and how exactly causality is violated if tachyons exist (which might as well go into the causality link.)
-- CYD
Hmmm... yes, it's a bit like saying "A unicorn might be like a fairy"... one fanciful thing being compared to another. Losing it doesn't hurt the article - good call. - MMGB
You MIGHT have magnetic monopoles which are also tachyons, but it's even closer to say that you might have unicorns which are also infrared. -- CIM --- I think the subject of tachyons is a rather delicate matter, more delicate than perhaps this article presents. That is, I changed "hypothetical" to "theoretical," in an attempt to distinguish between the theory and practice without the ladened hyperbole' (is that a fair description?). It seems to me that tachyons are quite a bit deeper than "fanciful things," where their existence may even end up being necessary in order to explain any number of real phenomena (see entanglement).
http://arxiv.org/abs/hep-ph/9905454
I am considering revamping this page a fair amount.
I look quite favorably upon the existence of magnetic monopoles simply because they lead to quantization of charge. I wasn't aware that they necessarily violated any laws of physics though. 142.161.183.184 06:22, 21 April 2006 (UTC)Matt
Considering that superpartners and even the Higgs are currently hypothetical particles, this adjective implies no opprobrium. If a particle exists "real" or "physical"; if it doesn't it's "fictional" or "unphysical"; if we don't know yet it's "hypothetical". In fact, "theoretical particle" is an oxymoron, because theories are made of ideas, not particles. "Theoretical particle physics" is not the physics of theoretical particles!
It should be said rather strongly that the hypothesis that tachyons exist as particles, and are able to interact with ordinary matter, is very hard to entertain, unless you throw away one of the main principles of particle theory. It would introduce logical paradoxes, that is self-contradictions, unless supplemented by some clever principle which no-one has yet been able to incorporate in a coherent way.
As of now there is no compelling, or even half-compelling, reason to try. Quantum entanglement does not require tachyons, since no energy or information is exchanged faster than c. The paper cited above from the 'arxiv' is on "superbradyons", not strictly tachyons, and is highly speculative. All the references are to the author's own previous work, i.e. no-one else works on this.
Also, the (now removed) link to Florentin Smarandache does not illuminate the topic, as far as I can see, since that page does not mention tachyons. However, see http://scienceworld.wolfram.com/physics/SmarandacheHypothesis.html .
Tdent 19:00, 13 May 2004 (UTC)
I nixed the comment in the introductory paragraph about George Sudarshan. I hate to play the card-carrying obnoxious physicist, but any remark like "is considered to be" is weasel terminology. The only reason it could belong in the introduction is if a fuller description followed below, with proper citations to both original journal articles and later retrospectives.
A couple months ago, an anonymous user ( 82.68.88.6) added a similar comment, "Discovery of tachyons is attributed to Indian scientist George Sudarshan who was nominated for the Nobel Prize six times." IMNSHO, this sounds like gushing from a partisan supporter—never mind that we shouldn't speak about the discovery of a hypothetical particle. The article on Sudarshan himself seems similarly toned; a good POV shakedown may be in order.
Anville 17:04, 17 Mar 2005 (UTC)
HAHA! This is what I'm talkin' about! This was clearly written with the layman in mind, not like the other incomprehensible mathematical garbage floating around Wikipedia. I salute the author/editor! 70.25.138.179
What happened to Feinberg? If he named the tachyon (I've heard he "invented" it...), shouldn't he be mentioned? Trekphiler 12:35, 18 December 2005 (UTC)
Yikes! A pre-print from 2005-12. Let's wait for some comments on this, before claiming a revolutionary breakthrough.
Pjacobi 12:42, 21 December 2005 (UTC)
This is paper ('physics/0511253’) is basically from the Cornell University Authorized website. www.wbabin.net - might have just lifted the paper. All the submissions here, University Online Library, are up to the university academic standards. The paper is a very revolutionary one itself. Those who are commenting here may first go through the paper. The university will never publish one paper with out the recommendation of an eminent person from the same field. The paper is available at arxiv.org - Dr. Ravi
Now I was told by a friend, who goes by "The basement man" that the only way to survive the comubstion etc. of a tachyon particle would be throuhg means of black body radiation. Now, is black body radiation truly possible, or is it just another theory? hit me up at, thanks.
http://www.xanga.com/LeUntouchable_xx
I have two points to make about the current revision [2], particularly the portion that addresses the theoretical scientific framework behind tachyons:
Assuming no objections, maybe if I have more time I will attempt to do a rewrite myself. Note that this is just purely a matter of the flow of information in the section; I'm not proposing to add or delete any information.
At the very least the principle of special relativity would have to be discarded.
I believe that sentence is erroneous. Indeed it is almost contradictory since one section ago, we just discuss the foundation of tachyons in the framework of Special Relativity itself! The main issue here is that tachyons can violate the principles of causality. But if I recall correctly, special relativity doesn't require causality per se; causality is more a principle that physicists generally believe to be true, but is otherwise independent of the framework of special relativity.
Thus I marked that sentence with a "citation needed" tag. If the sentence is fully accurate a citation from a reliable source shouldn't be too hard to find. Otherwise, please remove and/or revise that sentence. 24.16.27.166 04:23, 6 June 2006 (UTC)
I think there is a serious deficiency in this section. Tachyons, despite travelling FTL, do not violate causality because they can't be used to transmit information, due to the Gerald Feinberg reinterpretation principle. I'll dig out a reference and rewrite accordingly soon. -- Michael C. Price talk 21:27, 28 June 2006 (UTC)
I accept the current version. However, if we express all equation in four dimensional form, we do not need to use imaginary numbers. We can start with Lagrangian (§7.2, Gravitation (1973). W. H. Freeman, ISBN 0-7167-0344-0)
then we can choose
Since 3D velocity is
then velocity time component
Energy
And Lorentz transformation for tachyons can be written as
I've used these transformations to make the tachyon image. -- TxAlien 02:00, 6 September 2006 (UTC)
This sounds like noncense: "Tachyons (if they existed) could be used to transmit energy-momentum, but they can't be used for communication." By shannons law if you transmit energy you transmit information. Think about it: just modulate if and when, or how much energy you send, and you automatically send information. Ariel. 11:39, 8 November 2006 (UTC)
I would like to challenge the bit about tachyons as scalar fermions. I'm not familiar with Feinberg's work(and I can't access those journal articles right now to check it out), but this seems quite incongruous with things that I understand quite well. Consider the Higgs field near the maximum of its potential. This field is tachyonic but the quantization is performed using commutation relations. If it were fermionic, one would quantize by introducing non-trivial anti-commutators. So could someone explain to me what the passage in the text means? Maybe there is confusion with the term ghost field; these are fields which satisfy the wrong spin-statistics relation.
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light."
Not being up on this subject and just skimming through to get a gist of this subject. I'm no expert, but this makes little sense to a reader.
"not impossible" is a double negative. Double negatives don't help understanding. Should be "is possible". Then I have a problem because these are hypothetical particles with imaginary mass and have never been detected (I guess). Shouldn't this then read ...
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, theroetically it is possible for an object to exist which always moves faster than light."
However, this sentence is vague as well. It leaves the reader confused imho because how can a particle get to this point? The confusion arises because to get to superliminary speeds would seemingly be impossible from a subluminary speed. The particle would have to be created at FTL speeds. Therefore it should say so (or have I assumed too much)?
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, theroetically it is possible for an object to exist which always moves faster than light provided it was created at superliminary speed.""
Candy 08:06, 3 December 2006 (UTC)
The energy-momentum relation given in this article is incorrect, I have corrected it without changing any of the other mathematics on the page. If there are any inconsistencies that crop up from this I apologise... but really it should have been correct in the first place.
changed to
-- Jheriko ( talk • contribs) 11:21, 6 December 2006 (UTC)
Thanks. I was a little worried that by changing those lines I might have broken some other maths later...
-- Jheriko 17:32, 6 December 2006 (UTC)
Some time ago, I added a sentence to the first paragraph
To date, the existence of tachyons has been neither proven nor disproven.
which was later changed to
To date, the existencec of tachyons has not been shown.
According to the author, this change was because "it is not up to scientists to disprove the existence of tachyons". I only partially agree with this: if tachyons don't exist, it may be possible to come up with physical/mathematical proof of their nonexistence (i.e., a contradiction in existing laws of physics as yet undiscovered). I think it's important to point out that tachyons have never been shown to exist, but that their existence has never been explicitly ruled out either. How should it be worded? Sloverlord 12:33, 30 December 2006 (UTC)
What is the justification for moving the mass term to the other side of the equation? It seems to be arbitrary, just so you can get a real mass. Why should we expect any particle to obey a different energy-momentum relation? Also, although I don't seem to know as much about tachyons as some people on this page, I'm going to add a sentence about the implication of a theory predicting tachyons and the "physicalness" of tachyons, to the best of my knowledge. Please clarify it if I'm wrong. Rotiro 09:58, 14 March 2007 (UTC)
Hi, Rotiro asked me to look at the recent edits and comment on this discussion. Tachyons are kind of a funny subject but if thought of properly do not "doom" a theory or demonstrate inconsistency per se. It is best not to think of them as particles in the classical(or even first quantized) sense; this may in fact be inconsistent, I am not sure. But it is certainly consistent when you consider them as waves, or quanta of a field. Waves often have complex components to the energy; this just means that there is some exponential growth or decay as well as the oscillation. Recall waves propagate like so a complex energy means this isn't just a phase but rather grows or decays in time. In classical electrodynamics, when light propagates through some medium, the signal decays as the medium absorbs energy from the wave. But sometimes a system is unstable and a certain mode will increase with time. In field theory, this occurs with the Higgs mechanism. In that case, the potential is not simply quadratic and actually has a minimum. The field has the standard E-p relation at the top of the potential. This is unstable since the mass is imaginary and this mode will grow exponentially. But as it grows, one must take into account higher-order effects in the field magnitude and the E-p relation is no longer the simple quadratic one. This tames the exponential growth and makes the field settle to the minimum of the potential. There one can use the standard E-p relation again, but it now has real mass.
So the upshot, is that tachyons themselves are not signs of inconsistency, just instability. But if the instability is never tamed(if the field keeps growing exponentially) then it will become singular and then presumably inconsistent. Hope that helps. -- Joshua Davis 20:55, 14 March 2007 (UTC)
I see, thanks guys. Rotiro 02:58, 18 March 2007 (UTC)
I have deleted a link to an unpublished article very different from scientific concensus. Dan Gluck 18:57, 20 July 2007 (UTC)
It would appear that many people believe the Sudarshan particles (imaginary mass particles) might someday be shown to exist. This web page almost implies that they actually do as of today because it spends time writing about a model that has yet to agree with experiment. So I added a note to point it out clearly and in so many words, that even after 45 years, this model (like string theory) has produced absolutely nothing! Period!!! If anyone has any evidence that these things exist, I would like certainly like to know about it. Finally, it was my link that Dan Gluck deleted on the assumption that the article was unpublished. In fact, it has been published. (See my Wikipedia user account with user name Ernstwall.) Ernstwall I have no desire to get into a tourney of urination, but Dan has stated in no uncertain terms in his user account that he doesn't want to argue with "nobodys". I trust after reviewing my summary of my background he will not consider me to be a total nobody (maybe just a partial nobody?). Also, does pointing out the obvious fact, in no uncertain terms, that playing with the Sudarshan particle is at a dead end, violate Dan's "scientific consensus" or is it "scientific consensus" that these things exist? —Preceding unsigned comment added by Ernstwall ( talk • contribs)
I suggest we delete all but the first paragraph of "Modern interpretation: Quantum field theory" and move any non-duplicated material over to Tachyon condensation.-- Michael C. Price talk 21:11, 31 July 2007 (UTC)
I've adapted the title of the causality section to conform with the condensation section. Perhaps the "Modern Interpretation" prefix is superfluous for both sections, or we could make both subsctions of s "quantum field theory" section.. -- Michael C. Price talk 15:39, 14 November 2007 (UTC)
Can anyone please tell me which way the tachyon is to be perceived as moving in the diagrams ? In the second diagram which is the arriving view and which the departing view ? Many thanks. Oharrez 10:41, 6 August 2007 (UTC)Oharrez
Thanks for coming back. However you haven't answered the question in layman's terms; I am not a scientist so don't understand doppler. I just want to know whether the left-hand side ( or the right-hand side ) is the arriving view. Then I can deduce that the other -hand is the departing view. It's a fascinating diagram, it would be a pity to remove it. Much better to explain it, this is after all a layman's encyclopedia. Many thanks. Oharrez 20:27, 6 August 2007 (UTC)Oharrez
Thank you for the explanation and the improved caption to the diagrams. I suppose it's a bit like being overflown by a fighter-jet, you see the back end of the departing aircraft and then hear the roar of its engines as the sound-wave trundles on behind. Oharrez 09:09, 7 August 2007 (UTC)Oharrez
Thanks again for your comments but it strikes me that if we follow the supersonic jet analogy, instead of having one image that splits into two, both departing in opposite directions from the same point, we have two images or series-of-images/sounds, one arriving ( even if in reverse order ) and one departing. This is not the same as one image breaking into two and both departing from the same point. What do you think ? Oharrez 09:21, 8 August 2007 (UTC)Oharrez
(I changed to "keep" - see below)
I propose to delete the diagram as original research. I don't understand at all what's going on there. I believe the diagram should be understandable at least for the average PhD student in physics... Dan Gluck 12:07, 6 August 2007 (UTC)
I deleted the following paragraph, due to WP:NOTE, WP:V, WP:OR. This result has no citing (the citing leads to another encyclopeida with no source to support this specific claim), it has not been reproduced, and the model is highly non-mainstream.
Some modern presentations of tachyon theory have demonstrated the possibility of a tachyon with a real mass. In 1973, Philip Crough and Roger Clay reported a superluminal particle apparently produced in a cosmic ray shower (an observation which has not been confirmed or repeated) [3]. This possibility has prompted some to propose that each particle in space has its own relative timeline, allowing particles to travel back in time without violating causality. Under this model, such a particle would be a "tachyon" by virtue of its apparent superluminal velocity, even though its rest mass is a real number.
Because it was already on the other side.
Why did the tachyon cross the road?
Special Relativity, strictly as formulated in the original papers and in most textbooks, does not allow any particle moving faster than light.
Special Relativity theory works with one real time dimension and three real space dimensions. So having v being greater than c (and having imaginary numbers as the contraction/dilatation factor in Lorentz equations) requires extending special relativity to deal with complex numbers.
Once such mathematical extension to complex numbers is accepted, all the rest of the article is OK. However it would be inappropriate to assume such extension without explicitly stating it, especially because this article will be read by people with very different backgrounds, not only physicists.
I suggest the following paragraph, or something similar, to be included in the article:
Rigorously speaking, tachyons are incompatible to special relativity, at least as it is known today. One way to understand such incompatibility is to remark that in special relativity, time and each of the three space dimensions are represented by real numbers. When deducing special relativity equations, like Lorentz space-time transformations, it is unavoidable, at one point, to take the square root of the expression:
In fact, such square root is explicitly present in most of special relativity equations. If v is greater than c, then the abovementioned expression has a negative value and it has no square root in real numbers. So special relativity equations can not be deduced. Note that this problem is not solved by claiming that tachyons have zero mass or imaginary mass.
Although extending special relativity to deal with complex dimensions is mathematically feasible, currently there is no experimental evidence supporting a four complex dimensional space-time.
The following discussion regarding tachyons and special relativity assumes a somehow “extended” special relativity to deal with complex versions of space-time and mass.
—Preceding unsigned comment added by 189.24.6.58 ( talk) 03:31, 5 September 2007 (UTC)
I have removed the following cluase from the article: - "- but they don't exist anyway (by tachyon condensation)." I cannot see how such a preemptive dismissal of content without specific comments in the text itself explicitly identifying why such preemptive judgement is made is even remotely acceptable. It was stated by the editor who inserted the content that the issue was "discussed" on this talk page. "Discussion" and "consensus" are far from being the same thing. I would now ask the editors involved in this page whether they believe the content I removed should be included or not. If they indicate it should not, I would also request some input as to what alternate phrasing, if any, would be acceptable, so that we can determine what the existing consensus regarding this subject is. Thank you. John Carter 19:15, 13 November 2007 (UTC)
Arthur Clarke should not be used as a source for anything scientific. ScienceApologist 16:36, 14 November 2007 (UTC)
Dear John Carter. The reference of Peskin and Schroeder, on which the "they don't exist" entry relies, is the most common (and usually considered the best) text book on quantum field theory, making it the best source on the subject. If you find a source of equal quality which contradicts it, please let us know. Otherwise, this whole debate is pointless. Have a good day! Dan Gluck 18:50, 15 November 2007 (UTC)
Im not certain there is a wiki article about it but it has become a common internet scam to use 'tachyon' as some kind of mysterious holistic energy found in products certain sites sell, evidentally increasing the negative entropy of the human system and spontaniously healing/strengthening. I wonder if there is any way we can mention this? 12.206.61.50 ( talk) 21:23, 3 February 2008 (UTC)
The caption of this current image in this article is way too long, it takes up the whole length of the browser! WinterSpw ( talk) 02:30, 4 June 2008 (UTC)
At some point there are many similar charactheristics of both particules in which i find interesting.
1- They are both massless 2- They are both hypothetycal 3- They are both related to strings theory 4- Gravitational energy tends to be weak, so much its hard to be detected, but has unlimited range; tachyons tends to have infinite speed at low or zero energy. Being not a physicist i can hardly explain the correlation but thats somehow why i ask the question ;). —Preceding unsigned comment added by 96.20.61.73 ( talk) 09:56, 11 August 2008 (UTC)
I am quite convinced that if tachyons could be made they could be easily used to send information backwards in time. The Feinberg reinterpretation principle doesn't quite work. If I can create negative energy tachyons, I can construct an Alcubierre_drive, and if not, I can exclude the other solution as nonphysical. Either way, backwards information is within reach. 75.45.10.20 ( talk) 20:10, 21 September 2008 (UTC)JH
[Rewrite, tidy] This article on tachyons is much expanded since I last looked several years ago, however it seems that with expanded detail comes expanded speculation. My central complaint is that the article simply assumes and knows to much, and precognitively tells the us answers to questions that physics hasn't solved yet. As such it makes several quite obvious errors about causality and assumes that current models of Quantum Mechanics and Relativity are correct at all velocities (impossible for obvious reasons). Saying that "A is correct and everything else is wrong inevitably comes before the discovery that A is wrong too. Any real solution has to deal with Relativity, with non-locality, and Minkowski space time and gravitational curvature. - Oh dear that has already broken the Quantum based answer in this article. (Relativity maps gravity one way Quantum Mechanics another, at least one is wrong.)
[snip] ...
- Specifically tachyons can or might break causality. - This seems so obvious to me but then I am developing a model of causality that specifically allows for local causality breaking and copes far better with such things.
- Although Imaginary Mass is pretty much the standard model for the tachyon and can be derived directly from Relativity, it is hardly mentioned. - Maybe because it emerges from the wrong side of the physics.
- The third point is rather uglier, the article states an old saw about tachyon velocities. Well while not directly incorrect this assumes a great deal about the FTL universe (much of it wrong) and its really little more like angels dancing on the head of a pin.
(My OR shows that tachyons have a very complicated phase space and different maps and many different behaviors are quite possible, but some are not. [snip - not till published])
Finally on the section on New Age 'nonsense' I'm afraid that I may be partly responsible for some of this since I talked on the subject in several groups five or six years ago, and a lot of what appears now looks a little like my terminology of the time. One of the uncomfortable things about tachyon behaviour is how closely it models parts of 'psychic phenomena', and unfortunately I pointed that out. Where people like the 'New Agers' fall down of course is that no-one actually knows how to generate such things as large scale Quantum Coherence or tachyon transience - otherwise their bracelets and magic totems would already work.
Sorry if I am rather critical of the article but this is an irritation to me - I hate seeing something I know is incorrect. [Finally I have to apologize for the very poor quality of the previous version, written after a night of no sleep.] 22 Sept 2008,
Lucien86 (
talk)
12:45, 18 April 2009 (UTC)
If tachyons really exists, what difference if tachyons don't exists?The main clue for tachyons is to know what things would change if they exists.And if they don't exist, what things are changed? Agre22 ( talk) 03:38, 24 May 2009 (UTC)agre22
The comment(s) below were originally left at Talk:Tachyon/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Needs a longer lead Snailwalker | talk 00:37, 21 October 2006 (UTC) |
Last edited at 00:37, 21 October 2006 (UTC). Substituted at 22:09, 3 May 2016 (UTC)
This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 |
Tachyons arise in many versions of string theory.
Could tachyons be gravitons?
I think it appear only in the bosonic string theory?? no? -- Pascal Gauthier 09:22, 14 Mar 2007 (UTC)
Does anyone want to clarify this sentence? It is very confusing with the double negatives.
Tachyons is theorized to exist in universes with extra time dimensions. A universe with 1 space dimension and 3 time dimensions are comprised of only Tachyons.
Could anyone add a link to the name for particles at sub-luminal speeds? I forgot what the name was. -- Redge 11:54, 13 Jun 2004 (UTC)
Can anyone verify this? I removed it as it sounds highly dubious to me; in any case, it is too vague.
We might also need discussion about the wave front effect, virtual particles, and how exactly causality is violated if tachyons exist (which might as well go into the causality link.)
-- CYD
Hmmm... yes, it's a bit like saying "A unicorn might be like a fairy"... one fanciful thing being compared to another. Losing it doesn't hurt the article - good call. - MMGB
You MIGHT have magnetic monopoles which are also tachyons, but it's even closer to say that you might have unicorns which are also infrared. -- CIM --- I think the subject of tachyons is a rather delicate matter, more delicate than perhaps this article presents. That is, I changed "hypothetical" to "theoretical," in an attempt to distinguish between the theory and practice without the ladened hyperbole' (is that a fair description?). It seems to me that tachyons are quite a bit deeper than "fanciful things," where their existence may even end up being necessary in order to explain any number of real phenomena (see entanglement).
http://arxiv.org/abs/hep-ph/9905454
I am considering revamping this page a fair amount.
I look quite favorably upon the existence of magnetic monopoles simply because they lead to quantization of charge. I wasn't aware that they necessarily violated any laws of physics though. 142.161.183.184 06:22, 21 April 2006 (UTC)Matt
Considering that superpartners and even the Higgs are currently hypothetical particles, this adjective implies no opprobrium. If a particle exists "real" or "physical"; if it doesn't it's "fictional" or "unphysical"; if we don't know yet it's "hypothetical". In fact, "theoretical particle" is an oxymoron, because theories are made of ideas, not particles. "Theoretical particle physics" is not the physics of theoretical particles!
It should be said rather strongly that the hypothesis that tachyons exist as particles, and are able to interact with ordinary matter, is very hard to entertain, unless you throw away one of the main principles of particle theory. It would introduce logical paradoxes, that is self-contradictions, unless supplemented by some clever principle which no-one has yet been able to incorporate in a coherent way.
As of now there is no compelling, or even half-compelling, reason to try. Quantum entanglement does not require tachyons, since no energy or information is exchanged faster than c. The paper cited above from the 'arxiv' is on "superbradyons", not strictly tachyons, and is highly speculative. All the references are to the author's own previous work, i.e. no-one else works on this.
Also, the (now removed) link to Florentin Smarandache does not illuminate the topic, as far as I can see, since that page does not mention tachyons. However, see http://scienceworld.wolfram.com/physics/SmarandacheHypothesis.html .
Tdent 19:00, 13 May 2004 (UTC)
I nixed the comment in the introductory paragraph about George Sudarshan. I hate to play the card-carrying obnoxious physicist, but any remark like "is considered to be" is weasel terminology. The only reason it could belong in the introduction is if a fuller description followed below, with proper citations to both original journal articles and later retrospectives.
A couple months ago, an anonymous user ( 82.68.88.6) added a similar comment, "Discovery of tachyons is attributed to Indian scientist George Sudarshan who was nominated for the Nobel Prize six times." IMNSHO, this sounds like gushing from a partisan supporter—never mind that we shouldn't speak about the discovery of a hypothetical particle. The article on Sudarshan himself seems similarly toned; a good POV shakedown may be in order.
Anville 17:04, 17 Mar 2005 (UTC)
HAHA! This is what I'm talkin' about! This was clearly written with the layman in mind, not like the other incomprehensible mathematical garbage floating around Wikipedia. I salute the author/editor! 70.25.138.179
What happened to Feinberg? If he named the tachyon (I've heard he "invented" it...), shouldn't he be mentioned? Trekphiler 12:35, 18 December 2005 (UTC)
Yikes! A pre-print from 2005-12. Let's wait for some comments on this, before claiming a revolutionary breakthrough.
Pjacobi 12:42, 21 December 2005 (UTC)
This is paper ('physics/0511253’) is basically from the Cornell University Authorized website. www.wbabin.net - might have just lifted the paper. All the submissions here, University Online Library, are up to the university academic standards. The paper is a very revolutionary one itself. Those who are commenting here may first go through the paper. The university will never publish one paper with out the recommendation of an eminent person from the same field. The paper is available at arxiv.org - Dr. Ravi
Now I was told by a friend, who goes by "The basement man" that the only way to survive the comubstion etc. of a tachyon particle would be throuhg means of black body radiation. Now, is black body radiation truly possible, or is it just another theory? hit me up at, thanks.
http://www.xanga.com/LeUntouchable_xx
I have two points to make about the current revision [2], particularly the portion that addresses the theoretical scientific framework behind tachyons:
Assuming no objections, maybe if I have more time I will attempt to do a rewrite myself. Note that this is just purely a matter of the flow of information in the section; I'm not proposing to add or delete any information.
At the very least the principle of special relativity would have to be discarded.
I believe that sentence is erroneous. Indeed it is almost contradictory since one section ago, we just discuss the foundation of tachyons in the framework of Special Relativity itself! The main issue here is that tachyons can violate the principles of causality. But if I recall correctly, special relativity doesn't require causality per se; causality is more a principle that physicists generally believe to be true, but is otherwise independent of the framework of special relativity.
Thus I marked that sentence with a "citation needed" tag. If the sentence is fully accurate a citation from a reliable source shouldn't be too hard to find. Otherwise, please remove and/or revise that sentence. 24.16.27.166 04:23, 6 June 2006 (UTC)
I think there is a serious deficiency in this section. Tachyons, despite travelling FTL, do not violate causality because they can't be used to transmit information, due to the Gerald Feinberg reinterpretation principle. I'll dig out a reference and rewrite accordingly soon. -- Michael C. Price talk 21:27, 28 June 2006 (UTC)
I accept the current version. However, if we express all equation in four dimensional form, we do not need to use imaginary numbers. We can start with Lagrangian (§7.2, Gravitation (1973). W. H. Freeman, ISBN 0-7167-0344-0)
then we can choose
Since 3D velocity is
then velocity time component
Energy
And Lorentz transformation for tachyons can be written as
I've used these transformations to make the tachyon image. -- TxAlien 02:00, 6 September 2006 (UTC)
This sounds like noncense: "Tachyons (if they existed) could be used to transmit energy-momentum, but they can't be used for communication." By shannons law if you transmit energy you transmit information. Think about it: just modulate if and when, or how much energy you send, and you automatically send information. Ariel. 11:39, 8 November 2006 (UTC)
I would like to challenge the bit about tachyons as scalar fermions. I'm not familiar with Feinberg's work(and I can't access those journal articles right now to check it out), but this seems quite incongruous with things that I understand quite well. Consider the Higgs field near the maximum of its potential. This field is tachyonic but the quantization is performed using commutation relations. If it were fermionic, one would quantize by introducing non-trivial anti-commutators. So could someone explain to me what the passage in the text means? Maybe there is confusion with the term ghost field; these are fields which satisfy the wrong spin-statistics relation.
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light."
Not being up on this subject and just skimming through to get a gist of this subject. I'm no expert, but this makes little sense to a reader.
"not impossible" is a double negative. Double negatives don't help understanding. Should be "is possible". Then I have a problem because these are hypothetical particles with imaginary mass and have never been detected (I guess). Shouldn't this then read ...
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, theroetically it is possible for an object to exist which always moves faster than light."
However, this sentence is vague as well. It leaves the reader confused imho because how can a particle get to this point? The confusion arises because to get to superliminary speeds would seemingly be impossible from a subluminary speed. The particle would have to be created at FTL speeds. Therefore it should say so (or have I assumed too much)?
"In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, theroetically it is possible for an object to exist which always moves faster than light provided it was created at superliminary speed.""
Candy 08:06, 3 December 2006 (UTC)
The energy-momentum relation given in this article is incorrect, I have corrected it without changing any of the other mathematics on the page. If there are any inconsistencies that crop up from this I apologise... but really it should have been correct in the first place.
changed to
-- Jheriko ( talk • contribs) 11:21, 6 December 2006 (UTC)
Thanks. I was a little worried that by changing those lines I might have broken some other maths later...
-- Jheriko 17:32, 6 December 2006 (UTC)
Some time ago, I added a sentence to the first paragraph
To date, the existence of tachyons has been neither proven nor disproven.
which was later changed to
To date, the existencec of tachyons has not been shown.
According to the author, this change was because "it is not up to scientists to disprove the existence of tachyons". I only partially agree with this: if tachyons don't exist, it may be possible to come up with physical/mathematical proof of their nonexistence (i.e., a contradiction in existing laws of physics as yet undiscovered). I think it's important to point out that tachyons have never been shown to exist, but that their existence has never been explicitly ruled out either. How should it be worded? Sloverlord 12:33, 30 December 2006 (UTC)
What is the justification for moving the mass term to the other side of the equation? It seems to be arbitrary, just so you can get a real mass. Why should we expect any particle to obey a different energy-momentum relation? Also, although I don't seem to know as much about tachyons as some people on this page, I'm going to add a sentence about the implication of a theory predicting tachyons and the "physicalness" of tachyons, to the best of my knowledge. Please clarify it if I'm wrong. Rotiro 09:58, 14 March 2007 (UTC)
Hi, Rotiro asked me to look at the recent edits and comment on this discussion. Tachyons are kind of a funny subject but if thought of properly do not "doom" a theory or demonstrate inconsistency per se. It is best not to think of them as particles in the classical(or even first quantized) sense; this may in fact be inconsistent, I am not sure. But it is certainly consistent when you consider them as waves, or quanta of a field. Waves often have complex components to the energy; this just means that there is some exponential growth or decay as well as the oscillation. Recall waves propagate like so a complex energy means this isn't just a phase but rather grows or decays in time. In classical electrodynamics, when light propagates through some medium, the signal decays as the medium absorbs energy from the wave. But sometimes a system is unstable and a certain mode will increase with time. In field theory, this occurs with the Higgs mechanism. In that case, the potential is not simply quadratic and actually has a minimum. The field has the standard E-p relation at the top of the potential. This is unstable since the mass is imaginary and this mode will grow exponentially. But as it grows, one must take into account higher-order effects in the field magnitude and the E-p relation is no longer the simple quadratic one. This tames the exponential growth and makes the field settle to the minimum of the potential. There one can use the standard E-p relation again, but it now has real mass.
So the upshot, is that tachyons themselves are not signs of inconsistency, just instability. But if the instability is never tamed(if the field keeps growing exponentially) then it will become singular and then presumably inconsistent. Hope that helps. -- Joshua Davis 20:55, 14 March 2007 (UTC)
I see, thanks guys. Rotiro 02:58, 18 March 2007 (UTC)
I have deleted a link to an unpublished article very different from scientific concensus. Dan Gluck 18:57, 20 July 2007 (UTC)
It would appear that many people believe the Sudarshan particles (imaginary mass particles) might someday be shown to exist. This web page almost implies that they actually do as of today because it spends time writing about a model that has yet to agree with experiment. So I added a note to point it out clearly and in so many words, that even after 45 years, this model (like string theory) has produced absolutely nothing! Period!!! If anyone has any evidence that these things exist, I would like certainly like to know about it. Finally, it was my link that Dan Gluck deleted on the assumption that the article was unpublished. In fact, it has been published. (See my Wikipedia user account with user name Ernstwall.) Ernstwall I have no desire to get into a tourney of urination, but Dan has stated in no uncertain terms in his user account that he doesn't want to argue with "nobodys". I trust after reviewing my summary of my background he will not consider me to be a total nobody (maybe just a partial nobody?). Also, does pointing out the obvious fact, in no uncertain terms, that playing with the Sudarshan particle is at a dead end, violate Dan's "scientific consensus" or is it "scientific consensus" that these things exist? —Preceding unsigned comment added by Ernstwall ( talk • contribs)
I suggest we delete all but the first paragraph of "Modern interpretation: Quantum field theory" and move any non-duplicated material over to Tachyon condensation.-- Michael C. Price talk 21:11, 31 July 2007 (UTC)
I've adapted the title of the causality section to conform with the condensation section. Perhaps the "Modern Interpretation" prefix is superfluous for both sections, or we could make both subsctions of s "quantum field theory" section.. -- Michael C. Price talk 15:39, 14 November 2007 (UTC)
Can anyone please tell me which way the tachyon is to be perceived as moving in the diagrams ? In the second diagram which is the arriving view and which the departing view ? Many thanks. Oharrez 10:41, 6 August 2007 (UTC)Oharrez
Thanks for coming back. However you haven't answered the question in layman's terms; I am not a scientist so don't understand doppler. I just want to know whether the left-hand side ( or the right-hand side ) is the arriving view. Then I can deduce that the other -hand is the departing view. It's a fascinating diagram, it would be a pity to remove it. Much better to explain it, this is after all a layman's encyclopedia. Many thanks. Oharrez 20:27, 6 August 2007 (UTC)Oharrez
Thank you for the explanation and the improved caption to the diagrams. I suppose it's a bit like being overflown by a fighter-jet, you see the back end of the departing aircraft and then hear the roar of its engines as the sound-wave trundles on behind. Oharrez 09:09, 7 August 2007 (UTC)Oharrez
Thanks again for your comments but it strikes me that if we follow the supersonic jet analogy, instead of having one image that splits into two, both departing in opposite directions from the same point, we have two images or series-of-images/sounds, one arriving ( even if in reverse order ) and one departing. This is not the same as one image breaking into two and both departing from the same point. What do you think ? Oharrez 09:21, 8 August 2007 (UTC)Oharrez
(I changed to "keep" - see below)
I propose to delete the diagram as original research. I don't understand at all what's going on there. I believe the diagram should be understandable at least for the average PhD student in physics... Dan Gluck 12:07, 6 August 2007 (UTC)
I deleted the following paragraph, due to WP:NOTE, WP:V, WP:OR. This result has no citing (the citing leads to another encyclopeida with no source to support this specific claim), it has not been reproduced, and the model is highly non-mainstream.
Some modern presentations of tachyon theory have demonstrated the possibility of a tachyon with a real mass. In 1973, Philip Crough and Roger Clay reported a superluminal particle apparently produced in a cosmic ray shower (an observation which has not been confirmed or repeated) [3]. This possibility has prompted some to propose that each particle in space has its own relative timeline, allowing particles to travel back in time without violating causality. Under this model, such a particle would be a "tachyon" by virtue of its apparent superluminal velocity, even though its rest mass is a real number.
Because it was already on the other side.
Why did the tachyon cross the road?
Special Relativity, strictly as formulated in the original papers and in most textbooks, does not allow any particle moving faster than light.
Special Relativity theory works with one real time dimension and three real space dimensions. So having v being greater than c (and having imaginary numbers as the contraction/dilatation factor in Lorentz equations) requires extending special relativity to deal with complex numbers.
Once such mathematical extension to complex numbers is accepted, all the rest of the article is OK. However it would be inappropriate to assume such extension without explicitly stating it, especially because this article will be read by people with very different backgrounds, not only physicists.
I suggest the following paragraph, or something similar, to be included in the article:
Rigorously speaking, tachyons are incompatible to special relativity, at least as it is known today. One way to understand such incompatibility is to remark that in special relativity, time and each of the three space dimensions are represented by real numbers. When deducing special relativity equations, like Lorentz space-time transformations, it is unavoidable, at one point, to take the square root of the expression:
In fact, such square root is explicitly present in most of special relativity equations. If v is greater than c, then the abovementioned expression has a negative value and it has no square root in real numbers. So special relativity equations can not be deduced. Note that this problem is not solved by claiming that tachyons have zero mass or imaginary mass.
Although extending special relativity to deal with complex dimensions is mathematically feasible, currently there is no experimental evidence supporting a four complex dimensional space-time.
The following discussion regarding tachyons and special relativity assumes a somehow “extended” special relativity to deal with complex versions of space-time and mass.
—Preceding unsigned comment added by 189.24.6.58 ( talk) 03:31, 5 September 2007 (UTC)
I have removed the following cluase from the article: - "- but they don't exist anyway (by tachyon condensation)." I cannot see how such a preemptive dismissal of content without specific comments in the text itself explicitly identifying why such preemptive judgement is made is even remotely acceptable. It was stated by the editor who inserted the content that the issue was "discussed" on this talk page. "Discussion" and "consensus" are far from being the same thing. I would now ask the editors involved in this page whether they believe the content I removed should be included or not. If they indicate it should not, I would also request some input as to what alternate phrasing, if any, would be acceptable, so that we can determine what the existing consensus regarding this subject is. Thank you. John Carter 19:15, 13 November 2007 (UTC)
Arthur Clarke should not be used as a source for anything scientific. ScienceApologist 16:36, 14 November 2007 (UTC)
Dear John Carter. The reference of Peskin and Schroeder, on which the "they don't exist" entry relies, is the most common (and usually considered the best) text book on quantum field theory, making it the best source on the subject. If you find a source of equal quality which contradicts it, please let us know. Otherwise, this whole debate is pointless. Have a good day! Dan Gluck 18:50, 15 November 2007 (UTC)
Im not certain there is a wiki article about it but it has become a common internet scam to use 'tachyon' as some kind of mysterious holistic energy found in products certain sites sell, evidentally increasing the negative entropy of the human system and spontaniously healing/strengthening. I wonder if there is any way we can mention this? 12.206.61.50 ( talk) 21:23, 3 February 2008 (UTC)
The caption of this current image in this article is way too long, it takes up the whole length of the browser! WinterSpw ( talk) 02:30, 4 June 2008 (UTC)
At some point there are many similar charactheristics of both particules in which i find interesting.
1- They are both massless 2- They are both hypothetycal 3- They are both related to strings theory 4- Gravitational energy tends to be weak, so much its hard to be detected, but has unlimited range; tachyons tends to have infinite speed at low or zero energy. Being not a physicist i can hardly explain the correlation but thats somehow why i ask the question ;). —Preceding unsigned comment added by 96.20.61.73 ( talk) 09:56, 11 August 2008 (UTC)
I am quite convinced that if tachyons could be made they could be easily used to send information backwards in time. The Feinberg reinterpretation principle doesn't quite work. If I can create negative energy tachyons, I can construct an Alcubierre_drive, and if not, I can exclude the other solution as nonphysical. Either way, backwards information is within reach. 75.45.10.20 ( talk) 20:10, 21 September 2008 (UTC)JH
[Rewrite, tidy] This article on tachyons is much expanded since I last looked several years ago, however it seems that with expanded detail comes expanded speculation. My central complaint is that the article simply assumes and knows to much, and precognitively tells the us answers to questions that physics hasn't solved yet. As such it makes several quite obvious errors about causality and assumes that current models of Quantum Mechanics and Relativity are correct at all velocities (impossible for obvious reasons). Saying that "A is correct and everything else is wrong inevitably comes before the discovery that A is wrong too. Any real solution has to deal with Relativity, with non-locality, and Minkowski space time and gravitational curvature. - Oh dear that has already broken the Quantum based answer in this article. (Relativity maps gravity one way Quantum Mechanics another, at least one is wrong.)
[snip] ...
- Specifically tachyons can or might break causality. - This seems so obvious to me but then I am developing a model of causality that specifically allows for local causality breaking and copes far better with such things.
- Although Imaginary Mass is pretty much the standard model for the tachyon and can be derived directly from Relativity, it is hardly mentioned. - Maybe because it emerges from the wrong side of the physics.
- The third point is rather uglier, the article states an old saw about tachyon velocities. Well while not directly incorrect this assumes a great deal about the FTL universe (much of it wrong) and its really little more like angels dancing on the head of a pin.
(My OR shows that tachyons have a very complicated phase space and different maps and many different behaviors are quite possible, but some are not. [snip - not till published])
Finally on the section on New Age 'nonsense' I'm afraid that I may be partly responsible for some of this since I talked on the subject in several groups five or six years ago, and a lot of what appears now looks a little like my terminology of the time. One of the uncomfortable things about tachyon behaviour is how closely it models parts of 'psychic phenomena', and unfortunately I pointed that out. Where people like the 'New Agers' fall down of course is that no-one actually knows how to generate such things as large scale Quantum Coherence or tachyon transience - otherwise their bracelets and magic totems would already work.
Sorry if I am rather critical of the article but this is an irritation to me - I hate seeing something I know is incorrect. [Finally I have to apologize for the very poor quality of the previous version, written after a night of no sleep.] 22 Sept 2008,
Lucien86 (
talk)
12:45, 18 April 2009 (UTC)
If tachyons really exists, what difference if tachyons don't exists?The main clue for tachyons is to know what things would change if they exists.And if they don't exist, what things are changed? Agre22 ( talk) 03:38, 24 May 2009 (UTC)agre22
The comment(s) below were originally left at Talk:Tachyon/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Needs a longer lead Snailwalker | talk 00:37, 21 October 2006 (UTC) |
Last edited at 00:37, 21 October 2006 (UTC). Substituted at 22:09, 3 May 2016 (UTC)
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