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At last I was able to rewrite completely the article. Of course, it is only a draft and needs lots of improvements. I'm preparing myself some more pictures. Sorry I forgot to sign and add summary of changes! Javirl 14:20, 2 November 2005 (UTC)
I find this article lacks a guide. Sometimes it goes into too much technical detail in math and sometimes leaves things too vague. I think this article should be split into parts. In the first one the very idea should be explained, mostly Kadanoff blocking with pics. The second one should be for RGT, fixed points, relevant-irrelev.-marginal operators, the semigroup character and universality classes. As a third one, although historically it might have come first, I'd add renormalized perturbation theory: Callan-Symanzik and applications to particle physics. Then, links to more specific techniques: Real Space RG (BRG, DMRG...), Momentum Space RG (diagrammatic, exact RG), RPT... and finally a section on the history of RG techniques. As addenda, other topics may be mentioned: relation to fractals, conformal field theory, etc. If nobody is opposed, I'll put my hands to this in a few days. Javirl 16:24, 20 September 2005 (UTC)
What is an "infrared attractor"? Not found via google.... NealMcB 00:30, 2004 Jan 22 (UTC)
No, I've never heard these terms either. Nor can Google find "infrared repellor". However, the term infrared fixed point does appear many times. See http://www.lns.cornell.edu/spr/1999-08/msg0017563.html for a reference. Also, ultraviolet fixed point. -- The Anome 07:54, 14 May 2004 (UTC)
I doubt that the characterization of 'attractor' and 'repellor' are correct. You get a continuum limit if you have an ultraviolet fixed point. The critical point of a statistical field theory corresponds to an infrared fixed point. Each phase is controlled by an attractive fixed point in it, which is usually an infrared fixed point and corresponds to homogeneity and trivial correlations. Critical points are always unstable in at least one direction.
The article is atrocious in its present state. I'll come in for a cleanup soon. — Miguel 14:34, 2004 May 25 (UTC)
I have redirected renormalization to this page. This was the content of the renormalization stub article:
— Miguel 07:27, 2004 May 28 (UTC)
Hmmm... seems like there really should be a separate article on renormalization itself, maybe focusing more on techniques in diagrammatic QFT. It seems odd that the article attributes the notion of renormalization to Gell-Mann and Low; they were more associated with the renormalization group, right? Renormalization goes back at least to Schwinger, Feynman and Tomonaga, though they may not have fully realized what they were dealing with prior to the renormalization group concept. -- Matt McIrvin 03:06, 3 Oct 2004 (UTC)
I seem to recall that there are also a couple of Russians who wrote on the renormalization group before Gell-Mann and Low, but were not credited in the West until much, much later. I can't remember the names of the Russian physicists, nor have I been able to track down this bit of trivia. If I had to guess I'd say that Bogoliubov must have been one of them, but I might be wrong. — Miguel 08:15, 2004 Oct 4 (UTC)
The link to the beta function wrongly points to the mathematical Euler beta function. This is NOT what is called the beta function in RG. There the beta function describes the change of the coupling constant(s) with the scale parameter. -- CBL
This article is so poorly written one wonders if the contributors even understand what they are talking about. Junk it and start from scratch..... — Preceding unsigned comment added by 64.105.137.249 ( talk) 05:47, 31 December 2011 (UTC)
From this section it follows that for example temperature, pressure and volume are relevant observables. Translating back to the RG behaviour the magnitude of these observables is supposed to increase as the observed scale is increased. I don't see what that is supposed to mean. Perhaps someone could elaborate on this? -- MarSch 12:27, 4 May 2006 (UTC)
I removed a line about the number of microscopic interactions being of order 10^{-23}. Presumably, the editor who wrote this was thinking about atoms in a box. However, RG flow is relevant in many physical contexts; in most relativistic quantum field theories for example and this statement is not accurate there. I also added a line explaining why we see only particles of spin 0, 1/2 and 1 at low energies. cheers, Perusnarpk ( talk) 21:40, 30 July 2008 (UTC)
User:R.e.b. re-inserted the statement about there being 10^{-23} microscopic interactions. This is incorrect, hence I've removed the statement again. Please do not re-insert without justifying it here. Second, I've elaborated the explanation of why we see only particles of spin less than 1 at low energies. The idea I am trying to express is that the standard model is an effective field theory, just like other quantum field theories. Since, the interactions of particles with spin larger than 1 are necessarily irrelevant, we do not see these particles in a low energy effective theory. In a `theory of everything' like string theory, these particles are indeed predicted at high energies, of order, the string scale, but they decouple at observable energies. If my explanation is not clear, please refine or discuss here. 202.159.224.74 ( talk) 08:42, 10 August 2008 (UTC)
This statement, that I suspect is incorrect,is from the Momentum Space RG section
Momentum-space RG is usually performed on a perturbation expansion (i.e., approximation). The validity of such an expansion is predicated upon the true physics of our system being close to that of a free field system.
Please confirm that this indeed wrong or please elaborate on the details if it happens to be true. As far as I understand, the validity of any perturbation rests on the convergence properties of the perturbative series.
Shouldn't RG rather be a monoid, since a 1-element exists and semigroup is (not always, but often — and as well @wikipedia) defined without 1-element? -- CHamul 10:24, 14 November 2006 (UTC)
Unfortunately, this article does a poor job of explaining RG in a context independent of any particular application. Notably missing from it is any mention of RG in Chaos/Complexity theory, where it is critically important in Feigenbaum's proof of universality for a class of functions giving rise to chaos under a period doubling route. The article also reads -- as do many Wikipedia articles on technical topics -- like it is intended for specialists (though I wouldn't know why they would want to read it), as it contains impenetrable references to a raft of other things that were defined elsewhere. Article authors need to recognize that non-specialists turn to Wikipedia for definitions, and that the articles like this are of poor quality unless they are intelligible to someone not immersed in the field. —Preceding unsigned comment added by 98.228.35.247 ( talk) 20:21, 21 November 2010 (UTC)
I have a question. The article speaks about the "renormalization group", but nowhere does the article prove that there is a structure that forms a group. Is the renormalization group a group, or is it just another bad name in Physics? I study Physics. But the mathematical definitions tend to be a lot better, in the sense that they mean what one expects them to mean. In this case, I feel there is something I am not getting, because I don´t see what the group is and if it is useful to think of transformations in this way. So, is there a group hidden there, or is better to ignore the name and just read the article? -- 190.188.2.122 ( talk) 01:16, 17 February 2011 (UTC)
I consider myself quite familiar with elementary group theory, but even I can't understand the relation of this object with the mathematical notion of a group. From the above discussion, I gather that this is an abuse of terminology. If so, that has to be clarified.-- Jasper Deng (talk) 07:17, 11 August 2017 (UTC)
I think what irritates mathematians and mathematically inclined physicists about the naming is not that they “overthink things“, but that the language common in this field implies there being a mathematical object called “the renormalisation group”, and that the way to understand what's meant by “RG this” and “RG that”, is to first understand this object (As puzzling this attitude might seem to mathematically non-inclined physicists!). I slightly edited the first sentence to avoid giving this impression.
As an aside, i think more could/should be said about how exactly the name is a misnomer, including a more abstract perspective on RG topics that highlights the mathematical structures actually characteristic of what “RG” is, but that should propably be written by an expert on the topic, not by me. -- 88.68.128.13 ( talk) 13:33, 3 June 2020 (UTC)
It would be nice if the anonymous 178.197.254.3 editor discussed the object of his persistent edits reverted by JRSpriggs, soundly, in my opinion. Gell-Mann and Low, in the reference cited, went beyond formal solution of the finite renormalization group equation to an expression equivalent to the rise of the QED coupling with energy precisely as quoted in the LEP measurement. Beyond mainstream professional opinion, Prof Harald Fritzsch stakes his professional opinion on it, in print (would 178.197.254.3 require the specific citation? DOI:10.1142/S0217751X10049864). Do S & P do so in the papers quoted, in such specificity? Do B & S? Is the paternity of this type fo prediction contested? Please discuss, before tendentious repetitive repartee edits! Cuzkatzimhut ( talk) 20:35, 1 May 2011 (UTC)
The History section is quite messy and sometimes incorrect. For example, ΛQCD is not the value of the RG scale μ at which the coupling diverges, that is the Landau pole. ΛQCD is the value of μ at which the coupling reaches the value 1. This means that perturbation theory is no longer reliable for energy values below ΛQCD. — Preceding unsigned comment added by Swoun ( talk • contribs) 15:42, 24 February 2014 (UTC)
the integration constant μ0 is not what I called the QCD scale, but rather the Landau pole. Note that perturbative QCD (g < 1) is valid only for μ > Λ and not for μ > μ0. In particular, it is not valid for μ in the range Λ > μ > μ0 . This gives the meaning to Λ. Note also that a coupling constant is said to be strong, not only when it diverges, but if it is equal to or larger than 1. The notion of Λ is in this way more fundamental and there is no name to it in your terminology. If you are using references such as Peskin and Schroeder, they reserve the name Landau pole to a high-energy pole and call ΛQCD to a low-energy pole in asymptotically free theories. They ignore the important meaning of the above Λ. The fact that the QCD coupling blows up at some energy is not physically meaningful. The fact that it is 1 at some energy is meaningful: perturbation theory is no longer reliable (and therefore we should not even cross to the regime of energies where g > 1). Swoun ( talk) 01:13, 26 February 2014 (UTC)
I am just utilizing the mainstream definition, , in your notation, along with thousands.To avoid arid theological discussions like this, most modern practitioners normalize the first formula with a suitable number in the denominator and the Z mass instead of Λ , MZ, so the strong coupling is pegged to its value at the Z mass. In perturbation theory, 1 and ∞ are comparably useless, and nobody contemplates close values.
Links to "universality class" redirect here. This article gets as far as mentioning that universality classes exist, and then abruptly stops. To be complete, it really needs to contain some kind of technical explanation of what they are and how they arise. (Though I do agree with earlier comments that the article is way too technical, in the sense of being completely inaccessible to the kind of person who needs it most.) 240F:7C:FC1A:1:1003:C899:842E:E0A ( talk) 10:26, 17 December 2014 (UTC)
Go ahead. WP is a collaborative pursuit. Propose it here first. Cuzkatzimhut ( talk) 11:21, 19 December 2014 (UTC)
You evidently came to the wrong place. You probably wish to be briefed on critical exponents for which there is a link, and not waste time thrashing around chaos and RG. In any case, I hyperlinked the standard Zinn-Justin reference in Scholarpedia. My insistent point, however, is that the place for a nontechnical introduction to basins of attraction and critical exponent calculation and reduced surfaces is definitely not here---unless you think you can contribute something that others have wisely skipped. It would be hard work to vulgarize the Scholarpedia article for the math-avoidant crowd. Do due diligence and read up. Cuzkatzimhut ( talk) 21:17, 26 December 2014 (UTC)
There is another article, Universality (dynamical systems), that seems to cover some of the same ground as this one when it comes to universality classes. Perhaps they should be merged, or at least more systematically linked to one another. Unfortunately the other article suffers from the same problem as this one regarding universality classes, in that it's purely descriptive, lacking technical information about what universality classes actually are and why they have the properties they do. 240F:7C:FC1A:1:D50E:E423:8FA7:F411 ( talk) 01:49, 20 December 2014 (UTC)
I have noticed that the "Equation box" prevent the equations from being written in the pdf rendering of the page. I would suggest to remove them, or to find a different way to highlight them, which is compatible with the pdf creation. -- Oakwood ( talk) 02:26, 16 June 2015 (UTC)
Pls see Talk:Quantum field theory#Gratuitous removal of Ken Wilson's portrait. The fact that KGW is the one pioneer in the history of physics shaping the RG is not a matter of dispute, one hopes! Cuzkatzimhut ( talk) 14:38, 1 March 2017 (UTC)
Incontrovertibly an invitation to WP:OVERSIMPLIFY... Lies to children... Of course the article is technical: it is the heart of quantum field theory. The relativity article and the Poincare group article and the QM mech articles are technical too to the novice, but it is absurd to pretend this is not unavoidable. 95% of mathematical articles here are too technical. Physicists start appreciating the RG after 4-5 years of technical schooling, and arguably fully master it after 20. Hopefully the template will add a few short words to the outsider, but, if the experience of several articles in WP is a guide, this appears like the beginning of a streak of uncontrolled erosion. More and more vapid nitpicking qualifying weasel words are added, which signal to crowds of fussing outsiders to come in and sculpt the narrative, and the end result is massive defocussing and detraction form the main "message" of the article, usually relegated to the end, and parts of the narrative the perpetrators normally decouple from. This is the routine progression of philosopher- and historian-infested articles like the Uncertainty principle, for instance, where regularly the focus is eroded in favor of lies-to-children bloviation---until a brave soul removes the underbrush in a spasm of righteousness. This repetitive drama seriously compromises the quality and reliability of WP. Cuzkatzimhut ( talk) 15:22, 11 August 2017 (UTC)
There are not-so-few editors who feel that physics articles should primarily be expressed in "ordinary language". They'd argue that one loses most of the audience if the article goes technical. The problem with insisting on this approach is that an article will go from having, say, 5% of readers (assumed unfamiliar with the topic) understanding it into having 0% of readers actually understanding it, while the number of readers that believe they understand it go up substantially. Understanding single words, and even complete sentences doesn't mean understanding the message (or physics).
That said, physics culture (physicists absolutely refuse to define notions precisely unless perhaps at the threat of withdrawn morning coffee for a month) can certainly be perceived impenetrable. For instance, I'd like to see "length scale" and "energy scale" defined precisely. This might not be easy as textbooks offer hand-waving only, usually with reference to other undefined notions (it is supposed to be obvious what is meant). Note that this is an argument for more technicalities, not fewer, and also for less jargon. YohanN7 ( talk) 12:26, 7 September 2017 (UTC)
Electrons consisting of electrons(??????), positrons and photons. Bare electrons, dressed electrons, clothed electrons? It feels like someone is cheating here. Bad article ... again!!! — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 20:47, 26 October 2020 (UTC)
It is misleading to invoke the Avogadro number. The model space is something different and in principle can be much larger. For instance, the number of different chemical compounds consisting of C and H atoms grows more than exponentially with the number of atoms.
It is misleading to say that a relevant parameter "always grows". In what direction? In respect to what sign convention? Relevance, irrelevance and marginality describe the behavior in the vicinity of a fixed point. radical_in_all_things ( talk) 17:10, 15 November 2021 (UTC)
https://www.nature.com/collections/jbhcdccded Maybe cite. 2601:644:8501:AAF0:0:0:0:2034 ( talk) 00:35, 28 January 2024 (UTC)
This page is not a forum for general discussion about Renormalization group. Any such comments may be removed or refactored. Please limit discussion to improvement of this article. You may wish to ask factual questions about Renormalization group at the Reference desk. |
This article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||
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Daily pageviews of this article
A graph should have been displayed here but
graphs are temporarily disabled. Until they are enabled again, visit the interactive graph at
pageviews.wmcloud.org |
At last I was able to rewrite completely the article. Of course, it is only a draft and needs lots of improvements. I'm preparing myself some more pictures. Sorry I forgot to sign and add summary of changes! Javirl 14:20, 2 November 2005 (UTC)
I find this article lacks a guide. Sometimes it goes into too much technical detail in math and sometimes leaves things too vague. I think this article should be split into parts. In the first one the very idea should be explained, mostly Kadanoff blocking with pics. The second one should be for RGT, fixed points, relevant-irrelev.-marginal operators, the semigroup character and universality classes. As a third one, although historically it might have come first, I'd add renormalized perturbation theory: Callan-Symanzik and applications to particle physics. Then, links to more specific techniques: Real Space RG (BRG, DMRG...), Momentum Space RG (diagrammatic, exact RG), RPT... and finally a section on the history of RG techniques. As addenda, other topics may be mentioned: relation to fractals, conformal field theory, etc. If nobody is opposed, I'll put my hands to this in a few days. Javirl 16:24, 20 September 2005 (UTC)
What is an "infrared attractor"? Not found via google.... NealMcB 00:30, 2004 Jan 22 (UTC)
No, I've never heard these terms either. Nor can Google find "infrared repellor". However, the term infrared fixed point does appear many times. See http://www.lns.cornell.edu/spr/1999-08/msg0017563.html for a reference. Also, ultraviolet fixed point. -- The Anome 07:54, 14 May 2004 (UTC)
I doubt that the characterization of 'attractor' and 'repellor' are correct. You get a continuum limit if you have an ultraviolet fixed point. The critical point of a statistical field theory corresponds to an infrared fixed point. Each phase is controlled by an attractive fixed point in it, which is usually an infrared fixed point and corresponds to homogeneity and trivial correlations. Critical points are always unstable in at least one direction.
The article is atrocious in its present state. I'll come in for a cleanup soon. — Miguel 14:34, 2004 May 25 (UTC)
I have redirected renormalization to this page. This was the content of the renormalization stub article:
— Miguel 07:27, 2004 May 28 (UTC)
Hmmm... seems like there really should be a separate article on renormalization itself, maybe focusing more on techniques in diagrammatic QFT. It seems odd that the article attributes the notion of renormalization to Gell-Mann and Low; they were more associated with the renormalization group, right? Renormalization goes back at least to Schwinger, Feynman and Tomonaga, though they may not have fully realized what they were dealing with prior to the renormalization group concept. -- Matt McIrvin 03:06, 3 Oct 2004 (UTC)
I seem to recall that there are also a couple of Russians who wrote on the renormalization group before Gell-Mann and Low, but were not credited in the West until much, much later. I can't remember the names of the Russian physicists, nor have I been able to track down this bit of trivia. If I had to guess I'd say that Bogoliubov must have been one of them, but I might be wrong. — Miguel 08:15, 2004 Oct 4 (UTC)
The link to the beta function wrongly points to the mathematical Euler beta function. This is NOT what is called the beta function in RG. There the beta function describes the change of the coupling constant(s) with the scale parameter. -- CBL
This article is so poorly written one wonders if the contributors even understand what they are talking about. Junk it and start from scratch..... — Preceding unsigned comment added by 64.105.137.249 ( talk) 05:47, 31 December 2011 (UTC)
From this section it follows that for example temperature, pressure and volume are relevant observables. Translating back to the RG behaviour the magnitude of these observables is supposed to increase as the observed scale is increased. I don't see what that is supposed to mean. Perhaps someone could elaborate on this? -- MarSch 12:27, 4 May 2006 (UTC)
I removed a line about the number of microscopic interactions being of order 10^{-23}. Presumably, the editor who wrote this was thinking about atoms in a box. However, RG flow is relevant in many physical contexts; in most relativistic quantum field theories for example and this statement is not accurate there. I also added a line explaining why we see only particles of spin 0, 1/2 and 1 at low energies. cheers, Perusnarpk ( talk) 21:40, 30 July 2008 (UTC)
User:R.e.b. re-inserted the statement about there being 10^{-23} microscopic interactions. This is incorrect, hence I've removed the statement again. Please do not re-insert without justifying it here. Second, I've elaborated the explanation of why we see only particles of spin less than 1 at low energies. The idea I am trying to express is that the standard model is an effective field theory, just like other quantum field theories. Since, the interactions of particles with spin larger than 1 are necessarily irrelevant, we do not see these particles in a low energy effective theory. In a `theory of everything' like string theory, these particles are indeed predicted at high energies, of order, the string scale, but they decouple at observable energies. If my explanation is not clear, please refine or discuss here. 202.159.224.74 ( talk) 08:42, 10 August 2008 (UTC)
This statement, that I suspect is incorrect,is from the Momentum Space RG section
Momentum-space RG is usually performed on a perturbation expansion (i.e., approximation). The validity of such an expansion is predicated upon the true physics of our system being close to that of a free field system.
Please confirm that this indeed wrong or please elaborate on the details if it happens to be true. As far as I understand, the validity of any perturbation rests on the convergence properties of the perturbative series.
Shouldn't RG rather be a monoid, since a 1-element exists and semigroup is (not always, but often — and as well @wikipedia) defined without 1-element? -- CHamul 10:24, 14 November 2006 (UTC)
Unfortunately, this article does a poor job of explaining RG in a context independent of any particular application. Notably missing from it is any mention of RG in Chaos/Complexity theory, where it is critically important in Feigenbaum's proof of universality for a class of functions giving rise to chaos under a period doubling route. The article also reads -- as do many Wikipedia articles on technical topics -- like it is intended for specialists (though I wouldn't know why they would want to read it), as it contains impenetrable references to a raft of other things that were defined elsewhere. Article authors need to recognize that non-specialists turn to Wikipedia for definitions, and that the articles like this are of poor quality unless they are intelligible to someone not immersed in the field. —Preceding unsigned comment added by 98.228.35.247 ( talk) 20:21, 21 November 2010 (UTC)
I have a question. The article speaks about the "renormalization group", but nowhere does the article prove that there is a structure that forms a group. Is the renormalization group a group, or is it just another bad name in Physics? I study Physics. But the mathematical definitions tend to be a lot better, in the sense that they mean what one expects them to mean. In this case, I feel there is something I am not getting, because I don´t see what the group is and if it is useful to think of transformations in this way. So, is there a group hidden there, or is better to ignore the name and just read the article? -- 190.188.2.122 ( talk) 01:16, 17 February 2011 (UTC)
I consider myself quite familiar with elementary group theory, but even I can't understand the relation of this object with the mathematical notion of a group. From the above discussion, I gather that this is an abuse of terminology. If so, that has to be clarified.-- Jasper Deng (talk) 07:17, 11 August 2017 (UTC)
I think what irritates mathematians and mathematically inclined physicists about the naming is not that they “overthink things“, but that the language common in this field implies there being a mathematical object called “the renormalisation group”, and that the way to understand what's meant by “RG this” and “RG that”, is to first understand this object (As puzzling this attitude might seem to mathematically non-inclined physicists!). I slightly edited the first sentence to avoid giving this impression.
As an aside, i think more could/should be said about how exactly the name is a misnomer, including a more abstract perspective on RG topics that highlights the mathematical structures actually characteristic of what “RG” is, but that should propably be written by an expert on the topic, not by me. -- 88.68.128.13 ( talk) 13:33, 3 June 2020 (UTC)
It would be nice if the anonymous 178.197.254.3 editor discussed the object of his persistent edits reverted by JRSpriggs, soundly, in my opinion. Gell-Mann and Low, in the reference cited, went beyond formal solution of the finite renormalization group equation to an expression equivalent to the rise of the QED coupling with energy precisely as quoted in the LEP measurement. Beyond mainstream professional opinion, Prof Harald Fritzsch stakes his professional opinion on it, in print (would 178.197.254.3 require the specific citation? DOI:10.1142/S0217751X10049864). Do S & P do so in the papers quoted, in such specificity? Do B & S? Is the paternity of this type fo prediction contested? Please discuss, before tendentious repetitive repartee edits! Cuzkatzimhut ( talk) 20:35, 1 May 2011 (UTC)
The History section is quite messy and sometimes incorrect. For example, ΛQCD is not the value of the RG scale μ at which the coupling diverges, that is the Landau pole. ΛQCD is the value of μ at which the coupling reaches the value 1. This means that perturbation theory is no longer reliable for energy values below ΛQCD. — Preceding unsigned comment added by Swoun ( talk • contribs) 15:42, 24 February 2014 (UTC)
the integration constant μ0 is not what I called the QCD scale, but rather the Landau pole. Note that perturbative QCD (g < 1) is valid only for μ > Λ and not for μ > μ0. In particular, it is not valid for μ in the range Λ > μ > μ0 . This gives the meaning to Λ. Note also that a coupling constant is said to be strong, not only when it diverges, but if it is equal to or larger than 1. The notion of Λ is in this way more fundamental and there is no name to it in your terminology. If you are using references such as Peskin and Schroeder, they reserve the name Landau pole to a high-energy pole and call ΛQCD to a low-energy pole in asymptotically free theories. They ignore the important meaning of the above Λ. The fact that the QCD coupling blows up at some energy is not physically meaningful. The fact that it is 1 at some energy is meaningful: perturbation theory is no longer reliable (and therefore we should not even cross to the regime of energies where g > 1). Swoun ( talk) 01:13, 26 February 2014 (UTC)
I am just utilizing the mainstream definition, , in your notation, along with thousands.To avoid arid theological discussions like this, most modern practitioners normalize the first formula with a suitable number in the denominator and the Z mass instead of Λ , MZ, so the strong coupling is pegged to its value at the Z mass. In perturbation theory, 1 and ∞ are comparably useless, and nobody contemplates close values.
Links to "universality class" redirect here. This article gets as far as mentioning that universality classes exist, and then abruptly stops. To be complete, it really needs to contain some kind of technical explanation of what they are and how they arise. (Though I do agree with earlier comments that the article is way too technical, in the sense of being completely inaccessible to the kind of person who needs it most.) 240F:7C:FC1A:1:1003:C899:842E:E0A ( talk) 10:26, 17 December 2014 (UTC)
Go ahead. WP is a collaborative pursuit. Propose it here first. Cuzkatzimhut ( talk) 11:21, 19 December 2014 (UTC)
You evidently came to the wrong place. You probably wish to be briefed on critical exponents for which there is a link, and not waste time thrashing around chaos and RG. In any case, I hyperlinked the standard Zinn-Justin reference in Scholarpedia. My insistent point, however, is that the place for a nontechnical introduction to basins of attraction and critical exponent calculation and reduced surfaces is definitely not here---unless you think you can contribute something that others have wisely skipped. It would be hard work to vulgarize the Scholarpedia article for the math-avoidant crowd. Do due diligence and read up. Cuzkatzimhut ( talk) 21:17, 26 December 2014 (UTC)
There is another article, Universality (dynamical systems), that seems to cover some of the same ground as this one when it comes to universality classes. Perhaps they should be merged, or at least more systematically linked to one another. Unfortunately the other article suffers from the same problem as this one regarding universality classes, in that it's purely descriptive, lacking technical information about what universality classes actually are and why they have the properties they do. 240F:7C:FC1A:1:D50E:E423:8FA7:F411 ( talk) 01:49, 20 December 2014 (UTC)
I have noticed that the "Equation box" prevent the equations from being written in the pdf rendering of the page. I would suggest to remove them, or to find a different way to highlight them, which is compatible with the pdf creation. -- Oakwood ( talk) 02:26, 16 June 2015 (UTC)
Pls see Talk:Quantum field theory#Gratuitous removal of Ken Wilson's portrait. The fact that KGW is the one pioneer in the history of physics shaping the RG is not a matter of dispute, one hopes! Cuzkatzimhut ( talk) 14:38, 1 March 2017 (UTC)
Incontrovertibly an invitation to WP:OVERSIMPLIFY... Lies to children... Of course the article is technical: it is the heart of quantum field theory. The relativity article and the Poincare group article and the QM mech articles are technical too to the novice, but it is absurd to pretend this is not unavoidable. 95% of mathematical articles here are too technical. Physicists start appreciating the RG after 4-5 years of technical schooling, and arguably fully master it after 20. Hopefully the template will add a few short words to the outsider, but, if the experience of several articles in WP is a guide, this appears like the beginning of a streak of uncontrolled erosion. More and more vapid nitpicking qualifying weasel words are added, which signal to crowds of fussing outsiders to come in and sculpt the narrative, and the end result is massive defocussing and detraction form the main "message" of the article, usually relegated to the end, and parts of the narrative the perpetrators normally decouple from. This is the routine progression of philosopher- and historian-infested articles like the Uncertainty principle, for instance, where regularly the focus is eroded in favor of lies-to-children bloviation---until a brave soul removes the underbrush in a spasm of righteousness. This repetitive drama seriously compromises the quality and reliability of WP. Cuzkatzimhut ( talk) 15:22, 11 August 2017 (UTC)
There are not-so-few editors who feel that physics articles should primarily be expressed in "ordinary language". They'd argue that one loses most of the audience if the article goes technical. The problem with insisting on this approach is that an article will go from having, say, 5% of readers (assumed unfamiliar with the topic) understanding it into having 0% of readers actually understanding it, while the number of readers that believe they understand it go up substantially. Understanding single words, and even complete sentences doesn't mean understanding the message (or physics).
That said, physics culture (physicists absolutely refuse to define notions precisely unless perhaps at the threat of withdrawn morning coffee for a month) can certainly be perceived impenetrable. For instance, I'd like to see "length scale" and "energy scale" defined precisely. This might not be easy as textbooks offer hand-waving only, usually with reference to other undefined notions (it is supposed to be obvious what is meant). Note that this is an argument for more technicalities, not fewer, and also for less jargon. YohanN7 ( talk) 12:26, 7 September 2017 (UTC)
Electrons consisting of electrons(??????), positrons and photons. Bare electrons, dressed electrons, clothed electrons? It feels like someone is cheating here. Bad article ... again!!! — Preceding unsigned comment added by Koitus~nlwiki ( talk • contribs) 20:47, 26 October 2020 (UTC)
It is misleading to invoke the Avogadro number. The model space is something different and in principle can be much larger. For instance, the number of different chemical compounds consisting of C and H atoms grows more than exponentially with the number of atoms.
It is misleading to say that a relevant parameter "always grows". In what direction? In respect to what sign convention? Relevance, irrelevance and marginality describe the behavior in the vicinity of a fixed point. radical_in_all_things ( talk) 17:10, 15 November 2021 (UTC)
https://www.nature.com/collections/jbhcdccded Maybe cite. 2601:644:8501:AAF0:0:0:0:2034 ( talk) 00:35, 28 January 2024 (UTC)