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Krasnov framework for asymptotic safety in QG (Perimeter video)

  1. May 7, 2010 #1


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    Deformations of General Relativity
    Kirill Krasnov
    "I will describe a very special (infinite-parameter) family of gravity theories that all describe, exactly like General Relativity, just two propagating degrees of freedom. The theories are obtained by generalizing Plebanski's self-dual (chiral) formulation of GR. I will argue that this class of gravity theories provides a potentially powerful new framework for testing the asymptotic safety conjecture in quantum gravity."

    This Perimeter seminar video became available yesterday. I still can't watch it because the Flash version is not yet online.
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  3. May 7, 2010 #2
    Some promising ideas.
  4. May 7, 2010 #3


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    Thanks! I have long wnated to hear him speak.
  5. May 7, 2010 #4


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    There are some selected Krasnov links here (earlier papers and talks):
    Krasnov 2006 video lecture:
    Krasnov 2008 audio+pdf talk at the ILQGS:
    http://relativity.phys.lsu.edu/ilqgs/krasnov020508.aif [Broken]
    Krasnov and Gomez Gravity-Yang-Mills-Higgs unification by enlarging the gauge group:

    Other Krasnov links:

    Even though the Flash version is not yet available online, I was able to watch by starting the MP3 audio simultaneously with the "Windows Presentation" video (which on my system does not provide sound).
    With a little attention one can keep the silent video almost in synch with the separate MP3 audio.

    It's a good talk! Also he got a lot of questions from Lee Smolin, Laurent Freidel, and Niayesh Afshordi. There were others asking questions whom I didn't recognize. If anyone knows some others' names please indicate. Like the young shiny-domed guy in front of Afshordi. Or the trim middleaged American in white dressshirt sitting behind Smolin, who asked a lot of questions.

    The audience seemed seriously interested and focused--calm excitement. They all wanted to make sure they understood. Good audience.
    Last edited by a moderator: May 4, 2017
  6. May 8, 2010 #5
    I haven't seen the video yet(just listened to the mp3 and looked at the pdfs) but I think I heard Roberto Percacci ask a couple of questions at the end?
  7. May 15, 2010 #6


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    I didn't hear anyone I recognized as Percacci. Right at the end Laurent Freidel was asking and discussing a lot with Krasnov.

    The bald guy I mentioned earlier was Isabeau Premont-Schwarz. He asked a few questions.

    Smolin was naturally interested because the Lisi-Smolin-Speziale paper that just came out is along the same lines. Both could prove asymptotically safe and combine matter with gravity.
    Maybe with LSS it is easier to explore the matter angle and not as clear how to get the UV safety. While with Krasnov the matter hasn't been worked in yet but the handling of UV safety is clean and beautiful.

    Krasnov was invited by Florian Conrady, this time.

    Another person over near Afshordi that I thought I recognized was Razvan Gurau. A talk like this, that brings them all out, reminds me what a good place Perimeter is these days.
    Last edited: May 16, 2010
  8. May 17, 2010 #7
    Percacci is sitting next to Isabeau Premont-Schwarz and Dario Benedetti is also there.
  9. May 18, 2010 #8


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    Thanks! In future video seminars I will be able now to recognize these people, so I will know who is asking the questions.

    In this case you said that Percacci asked some near the end, and I found one at time 1:20:40
    or just after that. Also Benedetti posed a question to Krasnov around 1:25:50.

    Those most active in asking questions (Smolin, Freidel, Afshordi, Premont-Schwarz) might be ones whose future research could relate in some way to Krasnov's, I will keep a look out for that.

    Benedetti already has 3 papers on Asymptotic Safety all published in 2009. Percacci is a central figure in A.S. with many papers. Their interest and connection with what Krasnov was talking about is clear, even though they didn't ask as many questions as some of the others.
    Last edited: May 18, 2010
  10. May 18, 2010 #9
    So all of the work done in AS so far has been done with the metric. One reason for this is that the heat kernal expansions for the metric have been found and it seems technically harder to do it for non-metric gravity.

    If AS does want to start making contact with other background independent approaches to gravity a good start would be to start looking at these gravity actions Krasnov is working with.

    It seems appealing that gravity at a UV fixed point may be well described by something like LQG but that the flow to the IR leads to classical GR or GR+torsion. Of coarse thats a big leap.
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