Monte Carlo simulations of 4d simplicial quantum gravity

TL;DR

This paper investigates four-dimensional Euclidean quantum gravity using dynamical triangulations, providing evidence for a well-defined partition function and discussing potential ambiguities in the model's measure that could affect universality classes.

Contribution

It offers a straightforward introduction to the 4d simplicial quantum gravity model and presents evidence supporting the existence of an exponential bound and explores measure ambiguities.

Findings

Evidence for an exponential bound ensuring a well-defined partition function

Discussion of measure ambiguities potentially leading to different universality classes

Contradicts recent claims about the model's properties

Abstract

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.