A Lorentzian cure for Euclidean troubles

TL;DR

This paper discusses how Lorentzian dynamical triangulations and a specialized path-integral measure can address the unboundedness of the gravitational action, enabling a well-defined non-perturbative quantum gravity formulation.

Contribution

It introduces a Lorentzian approach and a non-trivial measure to suppress conformal divergences, advancing non-perturbative quantum gravity methods.

Findings

Lorentzian triangulations show no obstacle from unbounded actions.

A non-trivial measure suppresses conformal divergences.

Supports a well-defined non-perturbative path integral.

Abstract

There is strong evidence coming from Lorentzian dynamical triangulations that the unboundedness of the gravitational action is no obstacle to the construction of a well-defined non-perturbative path integral. In a continuum approach, a similar suppression of the conformal divergence comes about as the result of a non-trivial path-integral measure.