tom.stoer
Science Advisor
- 5,759
- 157
fair enough
Could be that you are right.I think even the Thiemann and Giesel dust quantization isnt LQG, is it?
sound judgment.You'd also fix things from string theory.
Maybe both need to die.
An interesting quote from page 2 of the paper:http://arxiv.org/pdf/1308.0040v1.pdf
Finally one of the most exciting outcomes of this work is that it may give new insights into how
to formulate a consistent dynamics on the discrete geometry of loop gravity. If we could assign a
continuous connection and triad to a given set of loop gravity data, we would be able to write the
continuous scalar constraint in terms of these fields. The piecewise-flat and piecewise-torsionless
nature of spinning geometries would reduce the scalar constraint to a more simple form which is
supported only on the two-skeleton, which may help to write a dynamics in terms of holonomies and
fluxes. If successful, this would provide for the firrst time an anomaly-free means to relate the dynamics
of loop gravity with the dynamics of general relativity.
glass half-full versus glass half-empty Here is the video of a talk Freidel recently gave about this:Thanks for the hint regarding this paper,
http://arxiv.org/abs/1308.0040
Spinning geometry = Twisted geometry
Laurent Freidel, Jonathan Ziprick
and thanks for citing the summary.
Please note "may", "could", "would, "would", "may", "if", "would".
Anyway, this is exactly what I identified as the main open issue in LQG, regardless whether it's in the canonical, SF or any other approach. We do not yet have a consistently quantized and regularized H,...
Yes, and every 3 or 4 years it magically becomes a different glass. This may be the way it is supposed to be---the way fundamental theory progresses, until everybody suddenly says "Oh, of course!"The glass is half-empty for years, but many advertise it to be half-full
The Hamiltonian glass remains the same, it remains half-empty and anomalous ...Yes, and every 3 or 4 years it magically becomes a different glass
I definitly agree.In any case it is an exciting rapidly moving field.
In any case it is an exciting rapidly moving field.
I'm glad you agree! I heard recently that the next Loops conference will be at Erlangen, which I believe is where you live. This could be fun for you, to see these people in action, if there is enough room and you can attend some of the talks.I definitly agree.
But LQG must be a static field - there's no Hamiltonian so it can't have evolved!I think it is misleading to depict Loop gravity (with cosmo sector) as a "glass half empty" that has been sitting around half empty--IOW a static picture. That is an impression someone might have who had not been paying attention.
A witty in-joke *chuckle chuckle* obviously as a field of research LQG is evolving rapidly and, I think, actually approaching its goal of a path integral formulation (with zero Hamiltonian).But LQG must be a static field - there's no Hamiltonian so it can't have evolved!
Quoting you for the sake of http://arxiv.org/abs/1310.7786Boundary formalism, PI, SF, ... doesn't help per se.
Either you have to define a consistent, anomaly-free constraint algebra incl. Hamiltonian constraint,
or you have to define a consistent, anomaly-free path integral including measure, effective action, ...
I don't see that either of these approaches has succeeded in providing such a consistent definition. For all constructions it is unclear whether this is the case.