Anyone interested in following LQG research may wish to listen to Frank Hellmann's talk.(adsbygoogle = window.adsbygoogle || []).push({});

Download the slides PDF first before starting the audio. He will say when to advance to the next slide as he goes thru the talk. This gives a clear concise overview of a reformulation of LQG led by Bianca Dittrich (MPI-Potsdam and now Perimeter)

Here is my 7 September post about it:

==quote==

Frank Hellmann's 4 September online seminar talk

http://relativity.phys.lsu.edu/ilqgs/hellmann090412.pdf

http://relativity.phys.lsu.edu/ilqgs/hellmann090412.wav

...

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For more information about the ILQGS series of talks:

http://relativity.phys.lsu.edu/ilqgs/

http://relativity.phys.lsu.edu/ilqgs/schedulefa12.html

==endquote==

We can be a little proud that several of today's most active Loop researchers have been PF members and have posted (some quite a lot) over the past several years--e.g. Hellmann, Vidotto, Corichi, Livine...

Hellmann's talk is about 3 papers, one of which has already appeared on Arxiv, the other two expected to appear soon. People who occasionally come with questions like "what is LQG" or who comment on possibly outmoded versions they have read about may want to check these papers out as they appear..

* B. Bahr, B. Dittrich, FH, W. Kaminski:

Holonomy Spin Foam Models: Definition and coarse graining.

(arxiv:1208:3388),

Holonomy Spin Foam Models: Boundary Hilbert spaces and canonical dynamics. (arxiv:soon)

* FH, W. Kaminski:

Holonomy Spin Foam Models: Asymptotic Dynamics of EPRL type(arxiv: soon+ε)

models.

The authors are at Perimeter, MPI-Potsdam (Albert Einstein Institute), and Cambridge DAMPT. The abstract for the first of the three papers is:

==quote==

We propose a new holonomy formulation for spin foams, which naturally extends the theory space of lattice gauge theories. This allows current spin foam models to be defined on arbitrary two–complexes as well as to generalize current spin foam models to arbitrary, in particular finite groups. The similarity with standard lattice gauge theories allows to apply standard coarse graining methods , which for finite groups can now be easily considered numerically. We will summarize other holonomy and spin network formulations of spin foams and group field theories and explain how the different representations arise through variable transformations in the partition function. A companion paper will provide a description of boundary Hilbert spaces as well as a canonical dynamic encoded in transfer operators.

==endquote==

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# Critical recorded seminar talk by PF member

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