Euclidian 4d quantum gravity with a non-trivial measure term

Understand

We explore an extended coupling constant space of 4d regularized Euclidean quantum gravity, defined via the formalism of dynamical triangulations.

• We add a measure term which can also serve as a generalized higher curvature term and determine the phase diagram and the geometries dominating in the various regions.
• A first order phase transition line is observed, but no second order transition point is located.
• As a consequence we cannot attribute any continuum physics interpretation to the so-called crinkled phase of 4d dynamical triangulations.