Talk:Weinberg–Witten theorem

Renormalization

The Weinberg-Witten theorem has absolutely nothing to do with renormalization... Phys 20:11, 18 September 2005 (UTC)

I do not understand why you claim this. In the abstract of the Weinberg-Witten paper they claim in the abstract that they are proving the non-existence of massless fields (composite or real) for j > 1 for theories that are renormalisable and have a Lorentz covariant energy-momentum tensor. It seems that renormalisability is very important to the proof of the theorems.

There is a similar statement that j>3/2 is impossible for a fundumental particle. As discussed in Weinberg's book The quantum theory of fields, Vol 1, page 243 that this statement can be wrong (he uses Kulza-Klein modes as a counter-example). The problems here occur in a semi-classical limit and can restrict the form of interactions, but does not show j>3/2 is impossible.

Sociology??

This article begins with this sentence:

Steven Weinberg and Edward Witten consider the so-called emergent theories to be misguided.

This doesn't tell the reader whether this article is about sociology, economics, psychology, biology, literary criticism, linguistics, or whatever.... You've read all the way through the first sentence and you still don't know that. Michael Hardy (talk) 05:15, 24 December 2008 (UTC)

Technical??

I am a Physics Master's student, with a good knowledge of QFT and there are substanaial part of the article I have trouble understanding parts of the article. This is an encyclopedia and such an article could do with simpler, better written text not an abstract for a scientific paper. —Preceding unsigned comment added by 213.100.252.248 (talk) 21:07, 8 April 2009 (UTC)

Tone

" So, they came up with a no-go theorem that excludes, under very general assumptions, the hypothetical composite and emergent theories. " Can't we do better than this tone wise? It's pretty embarrassing. --69.147.132.194 (talk) 05:26, 26 September 2009 (UTC)

"Particles with spin j greater than one" -- Why j? Is this someone's favourite variable?

Why is the spin in the first para identied as "spin j"? The variable isn't referred to anywhere else and the phrase "particles with spin greater than one" is perfectly clear without needing any variables at all. Unless there is some significance to j that I'm missing, this needless insertion of a variable is just puffed-up writing. Ross Fraser (talk) 08:04, 11 May 2011 (UTC)

That's just the style commonly used in papers, talks, colloqia. User:Linas (talk) 19:24, 18 November 2013 (UTC)

conformal field theory and infraparticles

I'm worried that the sections on conformal field theory and infraparticles may reflect someone's personal research agenda and should be removed. Two obvious problems are the 1) the implication that Weinberg-Witten doesn't apply to noninteracting singletons (i.e. free fields) even though we see the statement contradicted at the end of the section on Seiberg duality; 2) the claim that infra particles violate the continuity assumption even though Weinberg and Witten explicitly say they don't need a continuity assumption. When I've understood the proof of this theorem a little better, I may try to edit the page. — Preceding unsigned comment added by 129.49.62.33 (talk) 11:59, 11 June 2014 (UTC)