Exploring the Phase Diagram of Lattice Quantum Gravity

Abstract

We present evidence that a nonperturbative model of quantum gravity defined via Euclidean dynamical triangulations contains a region in parameter space with an extended 4-dimensional geometry when a non-trivial measure term is included in the gravitational path integral. Within our extended region we find a large scale spectral dimension of D_s = 4.04 +/- 0.26 and a Hausdorff dimension that is consistent with D_H = 4 from finite size scaling. We find that the short distance spectral dimension is D_s ~ 3/2, which may resolve the tension between asymptotic safety and holographic entropy scaling.