The phase structure of pure Regge gravity

TL;DR

This paper investigates the phase structure of four-dimensional pure Regge gravity using Monte Carlo simulations, revealing a new phase transition at negative coupling that could be crucial for defining a continuum limit.

Contribution

It compares Monte Carlo results with $Z_2$-link Regge theory and a group-theoretical lattice gravity formulation, identifying a continuous phase transition at negative coupling.

Findings

Extension of well-defined phase to negative coupling

Identification of a new phase transition

Evidence for a continuous transition potentially enabling a continuum limit

Abstract

We examine the phase structure of pure Regge gravity in four dimensions and compare our Monte Carlo results with $Z_2$-link Regge-theory as well as with another formulation of lattice gravity derived from group theoretical considerations. Within all three models we find an extension of the well-defined phase to negative gravitational coupling and a new phase transition. In contrast to the well-known transition at positive coupling there is evidence for a continuous phase transition which might be essential for a possible continuum limit.