Loop Gravity-watchers will be familiar with Etera Livine, Laurent Freidel, and David Louapre. David has been a sometimes poster at PF and both Livine and Freidel are among those whose Lorentzian spinfoam papers we discussed. Freidel and Louapre (with help from Livine) are preparing a series of papers on 2+1 dimensional quantum gravity of which the first is now available.

The ancestor of this series is

Laurent Freidel, “ A Ponzano-Regge model of Lorentzian 3-Dimensional gravity ”, Nucl. Phys. Proc. Suppl. 88 (2000) 237-240 , gr-qc/0102098.

The announced series of four papers, of which the first was just posted:

L.Freidel and D. Louapre,"Ponzano-Regge model revisited I: Gauge fixing, observables and interacting spinning particles"

http://arxiv.org./hep-th/0401076
L.Freidel and D. Louapre, “Ponzano-Regge model revisited II: Mathematical aspects; relation with Chern-Simons theory, DSU(2) quantum group and link invariant". To appear.

L.Freidel, E. Livine and D. Louapre, “Ponzano-Regge model revisited III: The Field Theory limit”. To appear.

L.Freidel and D. Louapre, “Ponzano-Regge model revisited IV: Lorentzian 3D Quantum Geometry”. To appear.

------other papers of possible related interest-------

L. Freidel and D. Louapre, “Diffeomorphisms and spin foam models,” Nucl. Phys. B 662, 279

http://arxiv.org/gr-qc/0212001
K. Noui and A. Perez “Three dimensional loop gravity coupled to point particles”, to appear.

----------miscellaneous-----

Links to a couple of things at PF here:

interesting post from "notevenwrong" about testability

http://www.physicsforums.com/showthr...657#post128657
I dont think there's any need for any of us to justify

or explain why we are interested in the kinds of physics that

we're interested in.

So I dont normally bother to explain why I like to

report current developments in Loop Gravity or discuss

new papers with anyone who might be interested. But

here I was being challenged to explain my excitement and

I talked about why it's interesting to me personally

(doesnt have to be to you, but you may be enthused by

some of the same things). It's a ramble though.

http://www.physicsforums.com/showthr...783#post128783