Gravitational Wilson Loop in Discrete Quantum Gravity

TL;DR

This paper investigates the gravitational Wilson loop in discrete quantum gravity, demonstrating the area law in strong coupling regimes and exploring how light matter influences this behavior, with implications for observable phenomena.

Contribution

It extends previous results on the gravitational Wilson loop to various discrete quantum gravity models and analyzes the impact of light matter on the area law behavior.

Findings

The area law is a common feature in non-perturbative lattice quantum gravity models at strong coupling.

Light matter can significantly modify the Wilson loop area law only if the matter particles are extremely light.

The study discusses potential observable consequences of these quantum gravity effects.

Abstract

Results for the gravitational Wilson loop, in particular the area law for large loops in the strong coupling region, and the argument for an effective positive cosmological constant discussed in a previous paper, are extended to other proposed theories of discrete quantum gravity in the strong coupling limit. We argue that the area law is a generic feature of almost all non-perturbative lattice formulations, for sufficiently strong gravitational coupling. The effects on gravitational Wilson loops of the inclusion of various types of light matter coupled to lattice quantum gravity are discussed as well. One finds that significant modifications to the area law can only arise from extremely light matter particles. The paper ends with some general comments on possible physically observable consequences.