Connecting Loop Quantum Gravity and String Theory via Quantum Geometry

TL;DR

This paper proposes a unified view of String Theory and Loop Quantum Gravity, suggesting they describe different regimes of a single quantum gravity framework, with key parameters being proportional.

Contribution

It introduces a novel connection between String Theory and LQG, linking their fundamental parameters and interpreting String Theory's action as an expectation value in LQG.

Findings

String tension and Barbero-Immirzi parameter are proportional.

Nambu-Goto action corresponds to LQG area operator expectation value.

Unified quantum gravity framework bridging LQG and String Theory.

Abstract

We argue that String Theory and Loop Quantum Gravity can be thought of as describing different regimes of a single unified theory of quantum gravity. LQG can be thought of as providing the pre-geometric exoskeleton out of which macroscopic geometry emerges and String Theory then becomes the \emph{effective} theory which describes the dynamics of that exoskeleton. The core of the argument rests on the claim that the Nambu-Goto action of String Theory can be viewed as the expectation value of the LQG area operator evaluated on the string worldsheet. A concrete result is that the string tension of String Theory and the Barbero-Immirzi parameter of LQG turn out to be proportional to each other.