Talk:Supersymmetry

Who is editing: Well, you don't need to be a rocket scientist to look at [1] (http://en.wikipedia.org/w/wiki.phtml?title=Special:Contributions&target=211.28.196.87) and see that the edits are done from Australia - well, let's call it Melbourne. Together with frequent edits of supersymmetry, Edward Witten, string theory, and superstring theory, you will also find equally many edits of mirror matter and dark matter (well, slightly more positive ones). Then you analyze who in the world tries to write articles about these highly problematic theories. If you find Robert Foot [2] (http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=find+a+foot%2Cr) from Melbourne among the two astrophysicists of this class, you will probably think the same thing about the identity of 211.28.*.*. --Lumidek 12:05, 20 Oct 2004 (UTC)

Much of this article was propagander. Lets not forget that there is no evidence that supersymmetry actually exists and this is the crucial point. So, I have fixed it up a bit to make it more reasonable.

I assume you are the same user (211.28.196.87) that has been repeated vandalizing this page. Please stop. I encourage you to read NPOV. Wikipedia is not a soapbox to express your own world view (if it were, I'd heavily edit the articles on astrology, etc.). This article should express the concept of supersymmetry as it is studied by physicists — most of whom, I remind you, believe that supersymmetry is relevant to real world physics. And please sign your posts. -- Fropuff 02:02, 2004 Oct 20 (UTC)

Actually Astrology and supersymmetry have a lot in common neither has experimental verification. The important point is that it doesn't make sense to believe in something without empirical evidence (this is actually the dictionary definition of 'fanatic'). Most scientists would tell you that experimental evidence is required before you should accept some hypothetical theory. It is true that there are fanatical physicists who believe in supersymmetry, but this doesn't prove anything. If opinion polls of physicists were a useful thing to do, then this should be quantified. E.g. exactly what proportion of physicsists believe in supersymmetry? Such polls are not conducted because their results would be quite meaningless. The article needs to be fair and balanced and should not be simply propagander. Egbert

Isn't it a bit redundant to describe the Standard Model yet again in this article? Phys

Yes, this article is unsatisfactory on several counts. It makes it sound as if supersymmetry is nothing but a proposed modification to the Standard Model, but in fact it is a generic type of symmetry possessed by an infinite class of possible field theories, of which the (minimal) supersymmetric standard model is just one. I also don't believe that supersymmetry has "fallen from favour" (perhaps it did for a while); people are hoping, even expecting, that the superparticles will turn up when the Large Hadron Collider begins operation. And certainly supersymmetry remains a mainstay of the theoretical scene - it's a property of M theory and of the superstring theories, for example, which are still the leading candidates for a Theory of Everything. Mporter

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From the previous version of this page:

It was first suggested in 1972 and researched with some vigor in the 1980s, but has since fallen from favour because none of the large numbers of particles predicted by the theory have been observed.

This statement is clearly bunk. Supersymmetry remains a heavily researched area of physics. It is almost impossible to get a degree in particle physics without studying supersymmetry at some point. To quote from Nobel Laureate Steven Weinberg's book on supersymmetry:

Nevertheless, because of the intrinsic attractiveness of supersymmetry and the possibility it offers of resolving the hierarchy problem, I and many other physicists are reasonably confident that supersymmetry will be found to be relevant to the real world, and perhaps soon.
-- S. Weinberg, The quantum theory of fields, Vol. 3 Cambridge University Press, Cambridge, 1999

I've made some minor modifications to this page to get it off to a better start. A lot of work still needs to be done. The whole business of the supersymmetric standard model should probably be moved to its own page.

Fropuff 06:24, 2004 Feb 15 (UTC)

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As a reader of this page, I'd like to know what the first anticommutation relation means physically. ie. for the Lorentz group this sort of equation tells you that if you do two rotations, then do them in the in the opposite order, you don't get back where you started from, but the final state is a different rotation of the original (given by the structure constants expansion). What does it mean to generate translations from two Qs??

Cmbant

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I've restored the paragraph about the anticommutation relation, which apparently got zapped when the "3+1 Minkowski spacetime" section went in. A great deal of SUSY work involves spacetimes which are not 3+1 Minkowski (any string theorist can provide examples). Consequently, I think some general math should go before the detailed discussion of specific cases. This general section needs work, too, possibly inserting material from the supplementary articles like Poincaré group and Weyl spinor.

Furthermore, I swapped the paragraph order around. People seeking background information on SUSY (say, when CNN gives their five-second sound bites about the Large Hadron Collider) would probably want to hear about particles, rather than the mathematical details of various group and field theories. (Just my guess. ;-)

Off the top of my head, I can think of several SUSY topics that appear in string theory, each of which should be worth mention somewhere. For example,

• state-space cuts necessary to produce SUSY in the Ramond and Neveu-Schwarz sectors
• how SUSY allows results obtained at zero coupling to be generalized to finite coupling
• preserving SUSY under spacetime compactification
• the relevance of the previous two items to black holes (and their thermodynamics)

Most of this sort of thing belongs in other articles, as these topics get abstruse fairly quickly.

Anville 19:26, 24 Aug 2004 (UTC)

Probably, there would be two classes of people reading this: Layman, most of whom wouldn't be able to understand the mathematical details (although I'm sure some could, especially if explained well) and physics (and possibly math) students, who would most definitely like to know the mathematical details. And physicists would probably know SUSY by heart... :) Phys 05:33, 25 Aug 2004 (UTC)

Naturally. Even physicists have to learn it for the first time somewhere, after all. I just expect that there are more lay-persons in the world than post-graduate physicists. With that in mind, the current ordering might be somewhat friendlier. (-;

There's some pretty forbidding stuff in the article, as it stands right now. I think even physics students don't get to representation theory for at least a semester after they first learn the boson/fermion distinction. (Ha ha, that's supposed to be a humorous underestimation.) It may reach the point where the 3+1 Minkowski material is too detailed for an article that purports to be about SUSY in general. If the skilled explicators watching this page decide the examples have to be given in all detail—if less detail just isn't worthwhile—then I'd say we create a page entitled "Examples of Supersymmetry" or some such. (Maybe "Mathematics" should be mentioned in the title too.) Ah, well, a thought for later.

The SUSY QM material is interesting enough, in my view, to warrant an article of its own (with the current material left here as a micropaedia-style introduction). It is comprehensible on an undergraduate level, after a semester or less of good, solid QM. What's more, it makes the anticommutator a bit more comprehensible, perhaps addressing the issues raised by Cmbant. The Cooper, Khare and Sukhatme review article listed under "References" even manages to suggest how using SUSY in a full-blooded QFT can restrict the value of the vacuum energy (a cosmological topic this article should mention). I only know three schools whose QM classes solve the hydrogen atom the way CKS and this article sketch: the University of Washington in Seattle, MIT, and the University of Pennsylvania. The list may well be longer.

I've also come across a paper (http://web.mit.edu/~bstacey/www/susy-paper.pdf) written for an audience of third-term QM students about SUSY QM and the Dirac Equation.

Anville 16:58, 25 Aug 2004 (UTC)

Yeah, I wouldn't mind seeing most of this stuff broken up into seperate pages, with this page serving as more or less of an overview; most of which should be understandable to the lay person. Something along the lines of:

• Supersymmetric standard model, discussing various ways of incorporating SUSY into the SM, including the MSSM.
• Supersymmetry algebra, where the detailed mathematics should go
• Supersymmetric quantum mechanics, for that material

At some point we should have a page discussing SUSY in dimensions other than four as well. -- Fropuff 21:47, 2004 Aug 25 (UTC)

I've moved a big chunk of the SUSY algebra section into its own article.

Anville 17:14, 11 Oct 2004 (UTC)

This week I've finally had enough "real work" that I can procrastinate on it and hack away at the Wikipedia instead. Consequently, I've moved most of the SUSY QM nitty-gritty into its own article, supersymmetric quantum mechanics.

Anville 16:02, 11 Nov 2004 (UTC)