## Renormalization" "The Early Period"

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\n\nA cite describes 1947-1951 as "the early period" of renormalization field theiries.\n\nCan anyone provide a concise justification for calling this "the early period"?\n\nWasn\'t renormalization going on as early as Lorenz?\n\nS. Schweber\nBrandeis University\n"The History of Renormalization Field Theories:\nThe Early Period 1947-1951"\n24 March 1992\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>A cite describes $1947-1951$ as "the early period" of renormalization field theiries.

Can anyone provide a concise justification for calling this "the early period"?

Wasn't renormalization going on as early as Lorenz?

S. Schweber
Brandeis University
"The History of Renormalization Field Theories:
The Early Period $1947-1951$"
24 March 1992


James Bowery wrote in message news:2c4d4d0a.0407181926.5c597cec@posting.google.com... > > > > > A cite describes $1947-1951$ as "the early period" of renormalization field > theiries. > > Can anyone provide a concise justification for calling this "the early > period"? Wasn't renormalization going on as early as Lorenz? {I think you mean Lorentz.} Renormalization is the arbitrary *removal* of infinities that occur in quantum theory. Prior to quantum field theory, no one 'renormalized' anything. There were problems with infinities in point-particle theoretical models of the electron. This goes back to J.J. Thomson's 1881 calculation that the energy of a spherical charge of radius a is $q^2/2a$. Thus when the radius of a Lorentzian electron goes to zero, the energy diverges linearly. Of course, there is no problem -- if the electron has a finite radius. {Note that Lorentz's electrons did have a finite radius.} But in quantum field theory, the electron is modeled as a mathematical point. Hence, the problem exists in quantum mechanics. The first "mature" idea for renormalization began with Hans Bethe, in 1947. Prior attempts to solve the infinity problem did not use the renormalization 'trick.' Hence, the early period for renormalization seems reasonable. > S. Schweber > Brandeis University > "The History of Renormalization Field Theories: > The Early Period $1947-1951$" > 24 March 1992 See "Conceptual Development of 20th Century Field Theories" by Cao, section 7.6. -- greywolf42 ubi dubium ibi libertas {remove planet for return e-mail}



Speaking classically, if the electron is a fundamental particle it must be point like due to SR. See Landau & Lifschitz, Classical mechanics on that. An extended electron would be hard to make covariant. Formally it appears we need a sort of renormalization here. And Landau Lifschitz actually derive some of the absurd results that result from the ad hoc renormalization in Classical Fieldtheory, including a runaway sollution to the self interaction of a charged point particle. (I suspect these can be avoided by using a proper regularization scheme).

## Renormalization" "The Early Period"

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nFrank Hellmann &lt;Certhas@gmail.com&gt; wrote in message\nnews:e2b39847.0407210725.1e70f8ba@posting.google.com...\n&gt;\ n&gt; Speaking classically, if the electron is a fundamental particle it\n&gt; must be point like due to SR. See Landau & Lifschitz,\n&gt; Classical mechanics on that.\n\n*Ahem*. I must humbly disagree with both you, and L&L (if indeed they state\nthat). Relativity is not quantum ... but it\'s also not classical physics.\n\n&gt; An extended electron would be hard to make covariant.\n\nBut \'covariance\' is not a classical physical concept. It is pure SR.\n\nLorentz\' 1904 paper (for example) shares most of the controlling equations\nwith Einstein\'s 1905 SR paper. (With the exception of Lorentz\' equation 5).\nLorentz had a simple extended electron as the basis. But you are correct,\nthat covariance is not found in Lorentz.\n\n&gt; Formally it appears we need a sort of renormalization here. And Landau\n&gt; Lifschitz actually derive some of the absurd results that result from\n&gt; the ad hoc renormalization in Classical Field theory, including a\n&gt; runaway sollution to the self interaction of a charged point particle.\n&gt; (I suspect these can be avoided by using a proper regularization\n&gt; scheme).\n\nI do not see a need for a renormalization, for there is no need for a\nclassical solution that depends solely upon SR. By 1916, (in his GR paper)\nEinstein abandoned \'pure\' covariance in SR. So this would seem to be a\npointless effort.\n\n--\ngreywolf42\nubi dubium ibi libertas\n{remove planet for return e-mail}\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>Frank Hellmann <Certhas@gmail.com> wrote in message
news:e2b39847.0407210725.1e70f8ba@posting.google.com...
>
> Speaking classically, if the electron is a fundamental particle it
> must be point like due to SR. See Landau & Lifschitz,
> Classical mechanics on that.

*Ahem*. I must humbly disagree with both you, and L&L (if indeed they state
that). Relativity is not quantum ... but it's also not classical physics.

> An extended electron would be hard to make covariant.

But 'covariance' is not a classical physical concept. It is pure SR.

Lorentz' 1904 paper (for example) shares most of the controlling equations
with Einstein's 1905 SR paper. (With the exception of Lorentz' equation 5).
Lorentz had a simple extended electron as the basis. But you are correct,
that covariance is not found in Lorentz.

> Formally it appears we need a sort of renormalization here. And Landau
> Lifschitz actually derive some of the absurd results that result from
> the ad hoc renormalization in Classical Field theory, including a
> runaway sollution to the self interaction of a charged point particle.
> (I suspect these can be avoided by using a proper regularization
> scheme).

I do not see a need for a renormalization, for there is no need for a
classical solution that depends solely upon SR. By 1916, (in his GR paper)
Einstein abandoned 'pure' covariance in SR. So this would seem to be a
pointless effort.

--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}

 Recognitions: Science Advisor Because the essentials often get lost in esoterica, I'd like to reiterate the truth of grewwolf's discussion of renormalization. In physics, by common consent, renormalization means a scheme(s) to remove infinities from QFT perturbation computations. It could mean something else, but , in the trade it does not. Feynman's diagrams made QED and QFT, accessible to the ordinary theorist-- Schwinger's formalism was nearly impossible for most, highly abstract, highly difficult. But, when you examine renormalization by means of Feynman diagrams, the program does not look to be quite so arbitrary; there is a strong physical logic to the scheme. The mathematics is something else. Regards, Reilly Atkinson


Frank Hellmann writes >Speaking classically, if the electron is a fundamental particle it >must be point like due to SR. See Landau & Lifschitz, Classical >mechanics on that. An extended electron would be hard to make >covariant. Can you explain in elementary terms why this must be true? -- Oz This post is worth absolutely nothing and is probably fallacious. BTOPENWORLD address about to cease. DEMON address no longer in use. >>Use oz@farmeroz.port995.com<< ozacoohdb@despammed.com still functions.



"greywolf42" wrote in message news:<10fvvofkigti984@corp.supernews.com>... > Frank Hellmann wrote in message > news:e2b39847.0407210725.1e70f8ba@posting.google.com... > > > > Speaking classically, if the electron is a fundamental particle it > > must be point like due to SR. See Landau & Lifschitz, > > Classical mechanics on that. > > *Ahem*. I must humbly disagree with both you, and L&L (if indeed they state > that). Relativity is not quantum ... but it's also not classical physics. > You also disagree with http://www.google.com/search?hl=en&i...=Google+Search Classical is in my experience commonly used to refer to all physics non quantum, conceivably even GR, when talking about the classical limits of some theory of quantum gravity, most notably LQG. http://www.google.com/search?hl=en&l...it&btnG=Search > I do not see a need for a renormalization, for there is no need for a > classical solution that depends solely upon SR. By 1916, (in his GR paper) > Einstein abandoned 'pure' covariance in SR. So this would seem to be a > pointless effort. Hu? Everytime you calculate point sources with Maxwells equations you are effectively using a renormalized mass. I don't know how putting EM onto a GR manifold changes things, perhaps somebody else can shed some light there, but basically I don't see how the result of an infinite self energy of a point charge should change in the context of GR.



Oz wrote in message news:... > Frank Hellmann writes > > >Speaking classically, if the electron is a fundamental particle it > >must be point like due to SR. See Landau & Lifschitz, Classical > >mechanics on that. An extended electron would be hard to make > >covariant. > > Can you explain in elementary terms why this must be true? It's not a prove they offer it's more of an argument, but imagine that the fundamental particle is somehow not pointlike but extended. Then if you apply the force to the one side it would immidiately be felt on the otherside, thus information would transverse the particle faster then the speed of light. If it can be dented and isn't "rigid" in some sense then it's not a fundamental particle but described by a continuum picture which arises (among other possibilities) as the limit of fundamental point particles with a certain density, interacting according to some more fundamental law.



"Frank Hellmann" wrote in message news:e2b39847.0407310729.29a58e6c@posting.google.com... > > "greywolf42" wrote in message news:<10fvvofkigti984@corp.supernews.com>... > > Frank Hellmann wrote in message > > news:e2b39847.0407210725.1e70f8ba@posting.google.com... > > > > > > Speaking classically, if the electron is a fundamental particle it > > > must be point like due to SR. See Landau & Lifschitz, > > > Classical mechanics on that. > > > > *Ahem*. I must humbly disagree with both you, and L&L (if indeed they > > state that). Relativity is not quantum ... but it's also not classical > > physics. > > You also disagree with > http://www.google.com/search?hl=en&i...QFT&btnG=Googl e+Search Yes, I do. Web sites aren't God. > Classical is in my experience commonly used to refer to all physics > non quantum, conceivably even GR, when talking about the classical > limits of some theory of quantum gravity, most notably LQG. > http://www.google.com/search?hl=en&l...sical+limit&bt nG=Search A specialized, common usage may have come up. However that doesn't change the original meaning of the term. (Relativity is non-newtonian and non-mechanistic.) Since this term describes a social convention, the meaning is not fixed. So we could both be right. > > I do not see a need for a renormalization, for there is no need for a > > classical solution that depends solely upon SR. By 1916, (in his GR > > paper) Einstein abandoned 'pure' covariance in SR. So this would > > seem to be a pointless effort. > > Hu? Everytime you calculate point sources with Maxwells equations you > are effectively using a renormalized mass. Well, yes. But that's a failing of using mathematical point particles. Classical EM does not use point particles. > I don't know how putting EM onto a GR manifold changes things, perhaps > somebody else can shed some light there, but basically I don't see how > the result of an infinite self energy of a point charge should change > in the context of GR. QED currently uses point particles. But QM did not always make this assumption. The assumption was originally made merely to make the math more tractable -- not as a description of reality. Since the effort is to find ways to connect a continuum theory with a quantum theory, it may be that this approximation may be removed. -- greywolf42 ubi dubium ibi libertas {remove planet for e-mail}



"Frank Hellmann" wrote in message news:e2b39847.0407310722.1c1f697e@posting.google.com... > > Oz wrote in message news:... > > Frank Hellmann writes > > > > >Speaking classically, if the electron is a fundamental particle it > > >must be point like due to SR. See Landau & Lifschitz, Classical > > >mechanics on that. An extended electron would be hard to make > > >covariant. > > > > Can you explain in elementary terms why this must be true? > > It's not a prove they offer it's more of an argument, but imagine that > the fundamental particle is somehow not pointlike but extended. Like a soliton, or a Penrose twistor. > Then > if you apply the force to the one side it would immidiately be felt on > the otherside, thus information would transverse the particle faster > then the speed of light. This claim is a non-sequiteur. It does not follow, except for perfect rigidity. And perfect rigidity is not needed for a fundamental particle. > If it can be dented and isn't "rigid" in some > sense then it's not a fundamental particle This is merely an argument-by-defintion. "Fundamental particles must be rigid, or they can't be fundamental particles." > but described by a continuum picture That is not the only option. Such could be formed from a particulate aether (such as Maxwell's corpuscular vortices). > which arises (among other possibilities) as the > limit of fundamental point particles with a certain density, > interacting according to some more fundamental law. Therefore, your conclusion is unsupported, due to faulty logic. -- greywolf42 ubi dubium ibi libertas {remove planet for e-mail}



Frank Hellmann writes >Oz wrote in message news:rt995.com>... >> Frank Hellmann writes >> >> >Speaking classically, if the electron is a fundamental particle it >> >must be point like due to SR. See Landau & Lifschitz, Classical >> >mechanics on that. An extended electron would be hard to make >> >covariant. >> >> Can you explain in elementary terms why this must be true? > >It's not a prove they offer it's more of an argument, but imagine that >the fundamental particle is somehow not pointlike but extended. OK. >Then >if you apply the force to the one side it would immidiately be felt on >the otherside, thus information would transverse the particle faster >then the speed of light. If it were a wave then this is simple reflection. We know particles can be seen as waves and this model simply makes the argument irrelevant. >If it can be dented and isn't "rigid" in some >sense then it's not a fundamental particle Why on earth not? It would still be indivisible (eg see thread on solitons). >but described by a >continuum picture which arises (among other possibilities) as the >limit of fundamental point particles with a certain density, I do not dispute that one can describe wavelike particles as some function involving pointlike particles. This doesn't make the pointlike sub-particles any more 'elementary' than the wave, indeed quite the contrary as they can only describe PART of the elementary particle. There are many threads here discussing virtual particles and all the true experts seem strongly of the opinion that they do not exist but are a convenient mnemonic for expansion terms the totality of which describe the particle. Similarly a 'pointlike' electron is merely a 'hardly virtual at all' equivalent and should be so considered. >interacting according to some more fundamental law. I don't see that either. Elementary particles ARE waves (they diffract etc etc) and obey the laws they do. I might just as well consider a segment of a circle as more 'fundamental' than the circle itself. -- Oz This post is worth absolutely nothing and is probably fallacious. BTOPENWORLD address about to cease. DEMON address no longer in use. >>Use oz@farmeroz.port995.com<< ozacoohdb@despammed.com still functions.

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