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Ashtekar on Recent Advances in LQG

  1. May 17, 2007 #1
  2. jcsd
  3. May 17, 2007 #2


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    Hi! ccdantas!
    I've read most of them. It's a good place to make a compilation.
    In http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.2222v1.pdf he says,
    p. 5 …. However the recent, much more complete and detailed analysis [2] has shown that the universe does recollapse in LQC and agreement with classical general relativity on amax is excellent. Even for universes which are so small that amax ≈ 30ℓPl, the classical Friedmann formula ρmin = 3/(8π Ga2max) holds to one part in 10−5 and the agreement improves greatly for ‘macroscopic’ universes, i.e., ones with macroscopic values of amax.
    and in
    http://arxiv.org/PS_cache/gr-qc/pdf/0612/0612104v2.pdf he says
    p. 30 … results hold even for universes with amax ≈ 25ℓPl and the ‘sharply peaked’ property improves as amax grows.
    And I say,
    Using the minimum scale … k = r = 1.3819765 ( see blog entry d = 2.763953198 Barbero-Immirzi parameter) and amax = 24ℓPl

    I think that there is a convergence of approaches.
    Big Bang is dead.
  4. May 17, 2007 #3


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    That was a good idea. Thanks, Christine.

    I just went to your blog and left a message but somehow it did not seem to register immediately. Perhaps you need to give the OK, or it was filtered.

    One detail was the first link, to Ashtekar's paper. It did not bring up the paper.
  5. May 17, 2007 #4
    Thanks, Marcus!

    I have fixed the link.:yuck:
    Your comment is there now.
    Only approved comments appear. I moderate all comments. :wink:

  6. May 17, 2007 #5
    btw, I have asked Okolow to send me his PhD thesis by email
    yesterday, and he sent me a copy today.

    I would have to ask his permission to make it available
    at my blog, though.
  7. May 17, 2007 #6


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    Christine, if the Loop researchers had football team positions based on their recent work, then, because of this paper, Ashtekar would be named Goalie

    and I think one of the Forwards (does a soccer-team have Forwards?) is Carlo Rovelli who has just scored a point.

    The loop-quantum-gravity vertex-amplitude

    Maybe since you live in Brazil you know more about soccer and can correct me on this:smile:

    the analogy is imperfect because in the case of research there is no "opposition"---unless it is Nature's own inscrutable nature---her love of concealment and surprise.

    I checked the wikipedia and it says there is forward football position called the "Playmaker" or "Trequartista"
    Last edited: May 17, 2007
  8. May 17, 2007 #7
    I can't help you, I'm not really very interested in soccer, sorry! :yuck:

    (However, I am interested in other sports. I once run a marathon and competed in bicycle races... perhaps I might find some analogy there, but I don't believe so)... :biggrin:

    This paper by Engle et al. is interesting.
    (btw just a little unimportant detail but I suppose they should be using the symbol \approx 0 for the weak constraints instead of = 0 right? It seems they are going into a big step there, I'll read their paper further, thanks)
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