- #351
Lawrence B. Crowell
- 190
- 2
MTd2 said:I thought the problem was with the representation of the embeding.
I think it is best to think physically. If one tries to just quantize basic gravity SO(3,1) you run into a gemish of trouble. The problem is that you can't define a vacuum state, but rather you have a whole set of them which are inequivalent. This is one reason for the euclideanization procedure. Yet that defines an instanton state, or the tunnelling of a cosmology. The transition from SO(4) ---> SO(3,1) is still problematic, and after all the universe is Lorentzian. On SO(4) connection are defined on a finite or compact group, and then under the tunnelling these connections are defined on a noncompact group and the number of solutions becomes "infinite." Physically this means that attempting to define a vacuum is problematic and the physics is not bounded below.
Lawrence B. Crowell