Everybody should listen to the the last 10-12 minutes of Steven Weinberg's 7 July Cern talk, drag the button so it starts at minute 58 and go to minute 70, where he stops and takes questions. http://cdsweb.cern.ch/record/1188567/ He describes his own work in progress in AsymSafe Cosmology, where he gets inflation and a graceful exit from inflation as a natural consequence of A.S. QG. There already was a paper by Martin Reuter and Alfio Bonanno about this. If you start out at the UV fixed point (at the highest energy/smallest scale/highest wavenumber) then you naturally get inflation because of the values of the running constants. And then as scale increases the constants run towards more normal levels and inflation naturally stops. The point is that Weinberg has now done his own paper about the same business. In inflation scenarios there always was a problem of "graceful exit". Once you have set up things with assumptions constructed so that inflation happens, how do you get inflation to stop? the RBW (reuter bonanno weinberg) scheme takes care of that. Also inflation scenarios always used to involve fantasizing an exotic "inflaton" field different from anything in known physics. The RBW scheme using AsymSafe QG avoids that bizarre conjecturing. It does not need an "inflaton" field to drive the inflation. The biggest point Weinberg made in his Cern talk was to highlight the paper of Percacci Codello Rahmede. He gave a 2008 date for it but I recall seeing it in 2007 preprint, and discussing it here at PF. Percacci is the senior author. It is where they truncated so as to allow a 7D UV critical surface and they still only got 3D. The first really convincing evidence that the UV fixed point (on whose existence the whole AsymSafe QG program depends) has a finite dimensional UV critical surface. There was a followup in 2008 by Saueressig, Benedetti, Machado which got similar results with a different truncation, still the critical surface was only 3D which is very good news. Weinberg reminds us that both sets of authors, Percacci et al and Saueresssig et al, were able to include matter and still have it work. Keep in mind the Percacci Codello Rahmede paper. It was a turning point in Weinberg's story. Seeing that result was the point where Weinberg came back into the game after 30 years. So this is a major QG research development and it needs a conference or workshop. And it should involve Percacci, Reuter, Bonanno, Weinberg, maybe also Saueressig, Benedetti... A conference is how you gauge the strength of a research thrust, is it taking on new people? How mainstream is it? Who are the major players? Well it turns out that Roberto Percacci and Dario Benedetti are organizing the conference. It is 3-8 November 2009 at Perimeter and here are the confirmed invited speakers so far: http://www.perimeterinstitute.ca/en/Events/Asymptotic_Safety/Invited_Speakers/ [Broken] ==quote== Confirmed Invited Speakers To Date Jan Ambjorn, Utrecht University Alfio Bonanno, INAF, Catania Daniel Litim, University of Sussex Max Niedermaier, University of Sussex Martin Reuter, Mainz University Frank Saueressig, CEA, Saclay Lee Smolin, Perimeter Institute B.F.L. Ward, Baylor University Steven Weinberg, University of Texas, Austin Jean Zinn-Justin, CEA, Saclay ==endquote== Smolin has a 1982 paper on this AsymSafe-type stuff that he did at IAS Princeton, not long after Weinberg proposed AsymSafe (1979). Weinberg cited Smolin's IAS paper (on gravity at small scale) in his recent Cern talk. Jan Ambjorn is a clear choice for invited speaker because of the close connection between AsymSafe and Causal Dynamical Triangulations (Ambjorn Loll...). They get the same running dimensionality result. Weinberg cited Ambjorn and Loll's work in his Cern talk. Daniel Litim organized a conference last fall (September 2008) in the UK that brought together these and allied approaches, with many of the same people. He is the main UK guy involved in this. Niedermayer is normally based in France, don't know why he is listed from Sussex, maybe on sabbatical there. It strikes me that the confirmed invited speakers at the Perimeter November conference (plus the conference organizers Percacci and Benedetti) are essentially the same people that Weinberg cited in the last 12 minutes of his Cern talk. Now we need to put the new AsymSafe QG research thrust into broader perspective. I will try to do that as time permits later today. We've been actively following AsymSafe here at PF ever since 2005 when Martin Reuter and Renate Loll were plenary speakers at the Loops 2005 conference. And especially after Reuter's talk at Loops 2007 where he reported the Percacci Codello Rahmede result. There are a lot of papers and links I could give, if anyone wants. The best review is Percacci's chapter written for Oriti's book Approaches to Quantum Gravity. The book is 600 pages and expensive but Percacci's chapter is free online at arxiv.