https://arxiv.org/pdf/1103.4602.pdf
*Curvature in spinfoams* Elena Magliaro and Claudio Perini Institute for Gravitation and the Cosmos, Physics Department, Penn State, University Park, PA 16802-6300, USA (Dated: June 10, 2018) We consider spinfoam quantum gravity. We show in a simple case that the amplitude projects over a nontrivial (curved) classical geometry. This suggests that, at least for spinfoams without bubbles and for large values of the boundary spins, the amplitude takes the form of a path integral over Regge metrics, thus enforcing discrete Einstein equations in the classical limit. The result relies crucially on a new interpretation of the semiclassical limit for the amplitudes truncated to a fixed 2-complex. The physical picture emerging from the spinfoam gravity is that of a discrete, combinatorial spacetime structure (a quantum foam of virtual geometries), where the Plank scale plays the role of a natural minimal length. Spinfoams are the result of the quantization of general relativity formulated as a constrained BF theory. @philipthrift -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/6b564d4b-3f0c-4fc0-80e4-87c359d8bf49%40googlegroups.com.
