Comments on: News From The Front, III

By: News From the Front, IV - Asymptotia

News From the Front, IV - Asymptotia — Mon, 23 Oct 2006 01:09:11 +0000

[...] Before reading the paper -if interested- you can quickly refresh your memory of some of the context and technology I use by reading this post, and the papers referenced within. Why? Because: The theories are defined naturally by starting with models that yield wellâ€”understood string theories and allowing a fluxâ€”like background parameter to take halfâ€”integer rather than integer values. [...]

By: At The Monastery | Cosmic Variance

At The Monastery | Cosmic Variance — Thu, 06 Jul 2006 17:27:01 +0000

[...] The above example is a rare case -especially in higher dimensional or “critical” string theory- where an exact computation allows one to track the dynamics of the vacuum of string theory in an off-shell formulation. (It is possible in several cute toy models of non-critical strings in low dimensions, such as those I’ve described in other posts here and here). This is the sort of thing of which we need a lot more before we have believable control over statements about what non-supersymmetric vacua of string theory are really up to. Until we have control over these issues, we’ve got to be very careful about what we’re doing in this context, taking explorations of such vacua -and phenomenological conclusions which may be drawn from them- as interesting, but highly tentative. [...]

By: Return to the Fold | Cosmic Variance

Return to the Fold | Cosmic Variance — Fri, 27 Jan 2006 08:06:48 +0000

[...] I always considered it a great loss to the field, over the years, as he is quite a remarkable fellow (he seems to have been lauded at another piano competition again), and several things happened in the field after he left that I always thought that he would enjoy, and moreover bring an interesting and valuable approach to. On the other hand, he was not lost to physics or high energy physics as a whole, and started a series of really creative and singular work in another area, as I’ll mention below. (Ironically, the scope of some of what we did in that last paper we wrote, with Simon Dalley and Anders Watterstam, has only been fully appreciated in some recent work of mine (with Durham Phd. student James Carlisle and USC undergraduate student Jeff Pennington), described in an earlier post. We knew in 1991-2 that we ahd something that would now be called “open-closed duality”, but it is part of an even nicer story, as partially uncovered by Klebanov, Maldacena and Seiberg….. read that post for more, and I should do the next part of that story one day.) [...]

By: Plato

Plato — Mon, 07 Nov 2005 17:42:23 +0000

A general link for the laypeople

By: Clifford

Clifford — Sun, 06 Nov 2005 01:34:58 +0000

Ambitwistor… I’d have to think about that……

-cvj

By: Ambitwistor

Ambitwistor — Sat, 05 Nov 2005 23:15:26 +0000

I think it’s fascinating how an entire string theory can be “hidden” within a simple ordinary differential equation. Are there any examples of field theories arising from ODEs in similarly “non-obvious” ways?

By: Clifford

Clifford — Sat, 05 Nov 2005 21:20:34 +0000

Well, it is much more than that in general……. its most common realisation is in the context of particle physics where it is a symmetry that relates states (e.g. particles) of integer spin (”bosons”) with particles of half integer spin (”fermions”). The first reason this is interesting is because conventional particle physics has a big separation of the roles of these two types of particle…. matter is made of fermions (quarks, electrons, etc) while force is carried by bosons (photons, gluons, etc)… so if Nature once had a phase where it was supersymmetric, then matter and force are united in that phase….. This is but one of the many reasons that supersymmetry is exciting….. Then, as JoAnne has pointed out, the consequences of the relics of supersymmetry can be quite profound, since supersymmetric scenarios predict particles that may show up at the LHC which may be the principal component of Dark Matter……! Supersymmetry may also be tied up with the unification of forces, the origin of mass…so many things…… so it is interesting for lots of reasons…

-cvj

By: Helge

Helge — Sat, 05 Nov 2005 16:05:36 +0000

Well a big thanks again to you Clifford

For everybody else interested. The paper Clifford was refering to, can be found at:
http://www.arxiv.org/abs/hep-th/9405029
Enjoy reading.

My summary of my understanding (which might be wrong) is: Supersymmetry is kinda like added like you add spin. You double the Hilbertspace. However, you also use a modified Hamiltonian.
How you modify it can be found in that paper. (Page 13).

Helge

By: Clifford

Clifford — Sat, 05 Nov 2005 14:32:21 +0000

Helge. Well, later is probably better for this… but the key point is that the potential u for the case of Gamma number of branes and the potential for the case Gamma+1 form a pair of “superpartner” hamiltonians. The transformation between the two is the famous “Backlund” transformation….but there’s a lot more to this….including how to write the whole story so that it has the same algebraic structure as supersymetry algebras in other systems…. where you can discuss supersymmetry breaking, etc…. have a look at the paper. Oh, there is an excellent review by F. Cooper et al, of supersymmtric QM. Search SPIRES for that name and title combination.

cheers,

-cvj

By: Helge

Helge — Sat, 05 Nov 2005 12:09:16 +0000

Hey Clifford
You are asking for it. So what is the supersymmetry transform of that Hamilitonian? Or is there one?
Like for Translations in “time” we would have z -> z + a
Or timereversal z -> -z
And yes I have wondered what supersymmetry is.

Cheers, Helge