Causal structure of spacetime and geometric algebra for quantum gravity

We construct a background independent model of spacetime from a minimal set of postulates of causality. The topology and geometry of spacetime can be derived from the model, instead of being postulated. We define a measure of causality and relate it to the noncommutative geometric algebra of spacetime coordinates. The geometric algebra formalism leads to the definition of a Euclidean action. The Euclidean action is positive definite and allows the path integral formulation of quantum gravity to be treated as statistical physics of a causal stochastic Markov field. DOI: 10.1103/PhysRevD.87.064022