Discrete Approaches to Quantum Gravity in Four Dimensions
- Renate Loll
- Living reviews in relativity
Dynamical triangulations of four-dimensional Euclidean quantum gravity give rise to an interesting, numerically accessible model of quantum gravity. We give a simple introduction to the model and discuss two particularly important issues. One is that contrary to recent claims there is strong analytical and numerical evidence for the existence of an exponential bound that makes the partition function well-defined. The other is that there may be an ambiguity in the choice of the measure of the discrete model which could even lead to the existence of different universality classes. 1 Contribution to the special issue of the Journal of Mathematical Physics on Quantum Geometry and Diffeomorphism-Invariant Quantum Field Theory, edited by Carlo Rovelli and Lee Smolin.