Spinny Foamy talk

Last Tuesday, Johnathan Engle gave a talk for the International Loop Quantum Gravity Seminar. The talk was on the new spin foam models that have been proposed this year; namley, this one by Engle, Pereira and Rovelli and this one by Freidel and Krasnov. We have been having some discussions on both papers here at the Nottingham group as well. The two things that seem to me more important are the possibility of getting a better understanding of the role of the Immirizi parameter, which for first time is appearing in spin foam models, and the possibility of checking which is the correct dynamics via semiclassical calculations.

The audio and the slides of Engle's talk are available at the above link. If you are interested in getting an idea of the current state of research in the LQG/spin foam community, I encourage you to listen to the full audio. About the last half of it is an hour-long discussion between (mostly) Rovelli and Freidel. For me it gave me a strong feeling of how little really is known, and how basic are the disagreements that are still possible between people follwing essentially the same research program. It is something what does not see so directly in papers or even in most conference talks.