Talk:Effective field theory

A point that this article misses is that (most theorists nowadays believe that) almost all the useful quantum field theories we have, including the Standard Model of particle physics, are effective field theories. That's the moral behind the renormalization group. -- CYD

Comment on concept that most (all?) field theories are Effective Field Theories
The point by CYD that most or all quantum field theories are effective field theories is, from the right perspective, an obvious inference. Since that's such an important point, I suggest it be stated explicitly, in the context of all physical theories which may be presumed, by their nature as human constructs, to be successive rungs on a series of ladders of approximate theories (ladders that one hopes are somehow linked together). Dratman (talk) 16:18, 23 April 2010 (UTC)

GR and EFT
Can someone give me their opinion on these edits that were done to the general relativity article? They impress me as an overly rosely view of the association between GR and EFT given the way things are discussed in this article. Pervect claims that these are reasonable edits, but I had not heard of this theory (or paradigm) before. --EMS | Talk 14:25, 28 August 2006 (UTC)

Philosophy and Renormalization Group
I added a brief section on the Philosophy of Effective field theories. This, I feel, is quite important and deserves a separate section.

I also rewrote the section on R-G flow since I felt that was not necessarily very clear. Perusnarpk (talk) 20:48, 30 July 2008 (UTC)

This is extremely unclear English: Presently, effective field theories are discussed in the context of the renormalization group (RG) where the process of integrating out short distance degrees of freedom is made systematic. Although this method is not sufficiently concrete to allow the actual construction of effective field theories, the gross understanding of their usefulness becomes clear through an RG analysis.

Would it be technically accurate to rewrite this as Effective field theories are broadly characterised by renormalization groups (RG), by means of which the process of integrating out short distance degrees of freedom is made systematic. But I give up here, because I tied to make any sense of the following sentence (what is the referent of "their usefulness", for example?) but had no success. Help, literate physicists! -- RM —Preceding unsigned comment added by 76.191.212.109 (talk) 08:31, 4 August 2008 (UTC)

Source Theory
Schwinger starting in the 1960s felt that quantum field theory as a fundamental theory was flawed, and should be replaced by "source theory". People had a hard time understanding what he was getting at, and this work was historically marginalized. But, in hindsight, I think all he was saying was that a quantum field theory is an effective field theory. While QCD is not just an effective field theory, QED is, and this is what he was thinking about most of the time. If source theory is the historical uncle of effective field theory, it might be best to include a proper treatment of source theory. I can't do it, because I haven't read Schwinger's stuff in enough detail. Perhaps the resemblance to effective field theory is only superficial.Likebox (talk) 21:59, 11 September 2008 (UTC)

accessible version
I have a college eduation in molecular biology, and i don't understand a word of this. perhpas it is me and maybe it is the article. I think one of you physicists should try and add an english language introCinnamon colbert (talk) 14:20, 10 March 2009 (UTC)

Added a link to Elementary Particle Reaction
This article refers to certain specific particle reactions, using notation which would not be comprehensible to most readers. To help improve this, I added a link to a new article Elementary Particle Reaction. Since there is no such article -- nor even an article that's a good match -- and since I don't feel ready to write that article, I redirected Particle Reaction to Chemical Reaction.

Before you (understandably) object that "Those are not chemical reactions!", please read the first paragraph of Chemical Reaction, which states that "... the general concept of a chemical reaction, in particular the notion of a chemical equation, is applicable to transformations of elementary particles...'" Dratman (talk) 15:55, 23 April 2010 (UTC)

In EFT there is no averaging
In the introductory there it says "Intuitively, one averages over the behavior of the underlying theory at shorter length scales to derive what is hoped to be a simplified model at longer length scales." But this is not true. Mathematically no averaging takes place. An EFT has to be distinguished from a Mean Field Theory (MFT) commonly used in condensed matter physics. For a more detailed discussion please take a look at the textbook "Effective Field Theories" of A. Petrov and A. Blechman. --Imperator 0 (talk) 02:51, 17 January 2019 (UTC)