Coexistence of LQG and String Theory?

[marcus]

OK so Waka is busy for the time being and unlikely to respond, but I want to comment on something or some things he said

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I am a string theorist at heart, but I'm continuously trying to learn about new ideas. After all, the largest breakthroughs have been made by bringing tools from one area of science to another (spontaneous symmetry breaking being a good example I suppose).
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This thread is about productive interchange between String and Loop (and I think one could ask more broadly about the possibility of carryover to and from other QG lines.)
How much and what is possible? How much is likely.

Most of us (if we hang around BtSM forum) know the work of Kirill Krasnov. He has co-authored with Rovelli and with Freidel. The currently prevalent Loop dynamics could be called EPRL-FK spinfoam dynamics, and he is the K there. He has very interesting ideas which he works on intently often seeming out of touch with the other Loop people.

So what is Krasnov doing tomorrow? He will be in Munich attending the Strings 2012. This is an example of what I think has to happen. What Waka called "bringing tools" or taking away tools. Redistributing useful pieces of flint chipped and shaped in various ways.

From my personal perspective I think it will be especially productive for String people to learn how Loopsters and Cosmologists think. Also maybe how the Asymptotic Safesters think, if Shaposhnikov can be included with them.

Loop is relatively advanced in cosmology. Two recent ones I think of (not perhaps the most important, just ones that come to mind):
Agullo Ashtekar Nelson http://arxiv.org/abs/1204.1288
Artymowski Dapor Pawlowski http://arxiv.org/abs/1207.4353

 

[atyy]

Actually, FK are the loop people I most associate with taking a covariant point of view that need not coennct with the canonical viewpoint - not Rovelli. So I am pleasantly surprised to hear francesca espouse that viewpoint!

Actually, maybe it'd be more accurate to say FC "A priori, a spin foam model of gravity need not be related to canonical loop quantum gravity (LQG). That is, a given model could be a viable quantization of gravity, and nevertheless do not have the kinematical boundary variables of canonical LQG. Such a thing is, at least, conceivable, since we have an analogous example at the classical level: Hilbert-Palatini gravity, which after the Hamiltonian analysis, does not lead to the connection formulation by Ashtekar and Barbero."