Arcadian Functor

occasional meanderings in physics' brave new world

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Marni D. Sheppeard

Tuesday, August 26, 2008

Strings 2008

Although we still await the upload of videos for the talks, most slides from Strings 2008 are available. The must see talks, related to twistor strings (and AdS/CFT, although we don't really care about that), include those by Dixon, Alday and Green. For blog coverage see Mottle, Jester and Woit.

Green's slides were the most surprising. I was just about to nod off after an initial inundation of stringy mumbo jumbo, when I saw the words
natural $SL(2,Z)$ generalization of Riemann zeta values.
Recall that so called zeta values are usually values of the Riemann zeta function for integer arguments. In M theory, these integers are 1-ordinals in the sense of Batanin, and are associated with 1-categorical structures. Now awake, I noticed the reference to the paper by Green et al on MZVs, which I may get around to reading eventually. The appendix is written by D. Zagier!

Update: Webcast here.

14 Comments:

Blogger L. Riofrio said...

Another great photo! That's a lovely lake view too. From the dome size, I am guessing that's a 12-inch reflecting telescope.

August 27, 2008 12:18 PM  
Anonymous Anonymous said...

Dear Kea,

on Woit's blog you write that it is impossible to construct a theory that contains *only* general relativity and the standard model. Could you state the arguments? (I have a friend insisting that such a theory is the way to go, so the arguments will be valuable to him...)

Thanks!

Frank Sheldon

August 27, 2008 5:02 PM  
Blogger Kea said...

Louise, yes, that's the Earth and Sky telescope that they use for tours on clear nights.

August 27, 2008 5:59 PM  
Blogger Kea said...

Frank, to me this is a self evident fact based on the nature of unifications in the past, but since you may not agree the only general argument for this is the large volume of evidence that we have been collecting for years now, and which I am quite unwilling to summarise in a few words. You are very welcome to peruse our blogs and linked papers.

August 27, 2008 6:04 PM  
Anonymous Anonymous said...

I did not want to start a discussion; I just wanted some of the arguments for my friend. I believe in arguments, not in discussions.

Some arguments are well known: perturbative instability of the Higgs, lack of coupling unification at high energy, unexplained equality of positron and proton charge, unexplained couplings, unexplained quark mixing angles, unexplained weak mixing angle, unexplained fermion masses and hierarchy problem. These arguments are usually given to call for extensions of the standard model. I just wondered if there were any more you had in mind.

Frank Sheldon

August 28, 2008 3:04 AM  
Blogger Kea said...

Incompatibility of quantum physics and GR, existence of dark matter, cosmological problems, the amount of effort that has already been wasted trying to do what your friend wants to do, the modern mathematical formulation of renormalization, results from condensed matter physics, .... the list is VERY, VERY LONG.

August 28, 2008 8:13 AM  
Anonymous a quantum diaries survivor said...

Really nice pic, you look great!

Did you stay the night ? What was
the limiting magnitude at that site ?

Cheers,
T.

August 29, 2008 7:59 AM  
Anonymous John G said...

Kea, so what's on the short list of things needed besides general relativity and the standard model? From reading here I might guess, at low energies, at least that 3,3 or 4,2 signature you and Tony Smith had talked about and at high energies something like the E8 to Leech/monster to category theory approach that you discussed with Smith more recently.

August 29, 2008 11:42 AM  
Blogger Kea said...

John, I don't think about quantum gravity as something 'tacked on to' GR + SM. That's not the way to understand anything. Such signature spaces are interesting, especially in relation to twistor strings, but only as certain limits or models of a much richer underlying structure.

August 29, 2008 12:41 PM  
Blogger Kea said...

Basic info about the observatory is here. I suppose I could ask some of the locals for a best magnitude on a dark night ....

August 29, 2008 5:27 PM  
Anonymous Anonymous said...

Thank you , Kea, for completing the argument list.

Frank Sheldon

August 29, 2008 6:32 PM  
Anonymous chimpanzee said...

Kea, Tommaso is asking a question that needs to be answered by a serious (visual) amateur astronomer. He has 1 of these cool electronic units to gauge limited magnitude. Visual amateur astronomy is frought with crackpots. Some of the so-called experts (book authors, etc) make wild claims about their visual prowess (limiting magnitude), just to enforce their egos (& pocketbooks, since they leverage their so-called experience to lead visual astronomy tours).

Are you living out in the boonies, near that telescope? You are in a perfect place to engage in some serious "amateur" astronomy. You should get a nice telescope, mount, binoculars. It looks like you have a digital camera now, it can be used to take some nice astrophotos (my specialty, see here). The Southern Sky is revered by many, including N. Hemisphere amateur astronomers. It have an incredibly rich set of nebulae, clusters. When I was in Carribean for '98 solar eclipse, the locals referred to the "Jewel Box" as "Diamonds in the Night".

August 29, 2008 9:20 PM  
Anonymous chimpanzee said...

How was that photo taken? With a self-timer, camera on a tripod? Or, was it with a friend's camera. You need fill flash to illuminate your face (which is barely discernible, but clearly beautiful). Wow, do you look pretty or what!

August 29, 2008 9:27 PM  
Anonymous John G said...

Kea, one could I would think have bosons (Standard Model and GR upgraded to a twistor-like signature) as a subalgebra of an algebra for quantum gravity (string theory, spin networks, Dirac gammas, etc.) but as you say, this quantum gravity would be some kind of limit of a much richer quantum gravity. Ideally one would want math that not only works in the easier to understand limit but also lets you venture out into the richer part.

August 30, 2008 5:08 AM  

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