Quantum gravity simulation

The quest for quantum gravity has been long and difficult. Causal Dynamical Triangulation (CDT) is a new and straightforward approach to quantum gravity that recovers classical spacetime at large scales by enforcing causality at small scales. CDT combines quantum physics with general relativity in a Feynman “sum over geometries” and converts the sum into a discrete statistical physics problem. This problem is then solved using a Hastings-Metropolis Monte Carlo simulation to compute the spatial fluctuations of an empty universe with one space and one time dimensions. The results compare favorably with theory and provide an accessible but detailed introduction to quantum gravity via a simulation that can be run from a laptop to supercomputers.