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marcus

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## Main Question or Discussion Point

In his most recent paper Martin Bojowald points to a threeway convergence towards a new formulation of background independent QG.

When he says this he points to three papers all from last year, one by Thiemann-Giesel (the first AQG, algebraic QG, paper), one by Ashtekar et al (going past the cosmo singularity), and one by Bojowald himself.

He says

Also THE KITP WORKSHOP WAS FULL OF THIS. So we have not only the papers of Thiemann, Ashtekar, Bojowald which he cites, we also have VIDEO TALKS by the same people, which show them using their new approach (if in fact Bojowald is right to call it new, and I suppose he is). So there is plenty of stuff for us to look at and get some help seeing what is going on.

The recent paper is:

http://arxiv.org/abs/gr-qc/0701142

Martin Bojowald

8 pages, plenary talk at the VIth Latin American Symposium on High Energy Physics (Puerto Vallarta, Mexico, Nov. 2006)

"Quantum gravity places entirely new challenges on the formulation of a consistent theory as well as on an extraction of potentially observable effects. Quantum corrections due to the gravitational field are commonly expected to be tiny because of the smallness of the Planck length. However, a consistent formulation now shows that key features of quantum gravity imply magnification effects on correction terms which are especially important in cosmology with its long stretches of evolution. After a review of the salient features of recent canonical quantizations of gravity and their implications for the quantum structure of space-time a new example for potentially observable effects is given."

When he says this he points to three papers all from last year, one by Thiemann-Giesel (the first AQG, algebraic QG, paper), one by Ashtekar et al (going past the cosmo singularity), and one by Bojowald himself.

He says

**all three represent a new departure because the state is a graph or lattice which is NOT EMBEDDED**in any smooth manifold, so there is no continuum except as a macroscopic illusion. He has more to say about it, but for starters there is something slightly new going on which we should probably try to be aware of. So I will give the links to those three papers which Bojo recent paper cites.Also THE KITP WORKSHOP WAS FULL OF THIS. So we have not only the papers of Thiemann, Ashtekar, Bojowald which he cites, we also have VIDEO TALKS by the same people, which show them using their new approach (if in fact Bojowald is right to call it new, and I suppose he is). So there is plenty of stuff for us to look at and get some help seeing what is going on.

The recent paper is:

http://arxiv.org/abs/gr-qc/0701142

**Quantum gravity and cosmological observations**Martin Bojowald

8 pages, plenary talk at the VIth Latin American Symposium on High Energy Physics (Puerto Vallarta, Mexico, Nov. 2006)

"Quantum gravity places entirely new challenges on the formulation of a consistent theory as well as on an extraction of potentially observable effects. Quantum corrections due to the gravitational field are commonly expected to be tiny because of the smallness of the Planck length. However, a consistent formulation now shows that key features of quantum gravity imply magnification effects on correction terms which are especially important in cosmology with its long stretches of evolution. After a review of the salient features of recent canonical quantizations of gravity and their implications for the quantum structure of space-time a new example for potentially observable effects is given."