The Quantum Dynamics of Causal Sets: Directions and Challenges

Abstract

I will begin with a short review of causal set theory (CST) focusing on the features that distinguish it from other approaches to quantum gravity. Most striking is a characteristic non-locality due to the Lorentz non-violating Poisson-discreteness in the continuum approximation. The discrete causal structure is rich enough, however, to extract local continuum geometric information, with geometric and topological observables corresponding to order-invariants in the causal set. These observables provide the necessary equipment in our search for a suitable quantum dynamics of causal sets. I will focus the rest of the talk on recent progress on this journey and the choices and challenges that lie ahead.