I sympathize strongly because I understand from Eric F that you are in graduate school where one's own research is almost a survival issue!Originally posted by Urs
...I don't know how much longer I will have the energy arguing that there are problematic steps if the people working on LQG won't agree with this assessment. Well, my goal is not to fix what I (and many others who explicitly told me so) consider problems of the LQG approach.
I would certainly understand you focussing your obvious talent and energy on your own favorite topics and not on "fixing the problems of LQG!"
If I were to try to sum up, in the simplest possible way, how you see these problems which you mention, I suppose I would say this (Is this correct?)
I believe you think that diffeomorphism invariance should be implemented by operator equations on the kinematical state space----constraint equations. these operators will correspond to generators of the diffeomorphism group.
I believe you wouold reject the fairly elementary and transparent construction on page 4 of
(the Fairbairn/Rovelli paper)
which defines a projection map from a preliminary hilbertspace
containing some unphysical redundancy down to the more concrete kinematical state space. This seems to be the thrust of your comment,
or perhaps you would describe it differently.
I am still trying to apply your reasoning to Rovelli's book or to this paper and to see clearly whether it amounts to anything *in that context*. I want to see what, if anything, your comments say about LQG proper not just about the Thiemann "Loop-String" paper, which (although it got quite some attention from those doing string research) seems somewhat periferal to the main body.
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