View Single Post
Feb26-12, 01:59 PM
Sci Advisor
P: 5,451
Quote Quote by marcus View Post
Personally I am not sure about the precise relation of the Crane-Yetter model (a topological quantum field theory) to quantum gravity.
Alexandrov explains this in detail.

It's not about the relation between CY and QG; it's about the quantization method.

Alexandrov shows that using the EPRL and FK method in case of the CY model explicitly gives us a wrong result (there are several ways to derive the CY model, so the SF rep. is well-known); then he uses a different method to implement the constraints (Dirac + delta-function in the measure) and he finds the correct CY vertex.

So the conclusion is that the method used by EPRL and FK is wrong.