Graviton propagator as a tool to test spinfoam models

Abstract

I briefly review the advancements in the construction of the graviton propagator in the context of LQG and Spinfoam Models. In particular the problems of the Barrett-Crane vertex in giving the correct long-distance limit and the introduction of the new corrected models. This kind of calculation applied to an alternative vertex with given asymptotic can give the correct propagator and is then able to help selecting spinfoam models. In particular the study of the asymptotic properties of the new models shows the predicted behavior able to overcome the BC difficulties and to give the correct propagator