Quantum gravity and the cosmological constant: lessons from two-dimensional dilaton gravity

TL;DR

This paper explores how quantum constraints in a two-dimensional dilaton gravity model can provide insights into the cosmological constant problem, offering a non-perturbative quantization approach and a spectrum of possible  values.

Contribution

It introduces a non-perturbative quantization of 2D dilaton gravity coupled to matter, linking quantum states to the cosmological constant in a novel way.

Findings

Derived an expression for  in terms of quantum states

Identified the roles of classical and quantum gravity in 

Presented a partial spectrum of  values

Abstract

In the investigation and resolution of the cosmological constant problem the inclusion of the dynamics of quantum gravity can be a crucial step. In this work we suggest that the quantum constraints in a canonical theory of gravity can provide a way of addressing the issue: we consider the case of two-dimensional quantum dilaton gravity non-minimally coupled to a U(1) gauge field, in the presence of an arbitrary number of massless scalar matter fields, intended also as an effective description of highly symmetrical higher-dimensional models. We are able to quantize the system non-perturbatively and obtain an expression for the cosmological constant \Lambda in terms of the quantum physical states, in a generalization of the usual QFT approach. We discuss the role of the classical and quantum gravitational contributions to \Lambda and present a partial spectrum of values for it.