Consistency check on the fundamental and alternative flux operators in loop quantum gravity

TL;DR

This paper uses graphical calculus to verify the consistency of different flux operators in loop quantum gravity, correcting a key parameter in the volume operator and simplifying previous algebraic methods.

Contribution

It introduces a graphical calculus approach for consistency checks in loop quantum gravity, providing a simpler alternative to algebraic calculations and refining the volume operator parameter.

Findings

Graphical calculus confirms flux operator consistency

Corrects the regulating factor of the volume operator to 1/2

Simplifies the verification process compared to algebraic methods

Abstract

There are different constructions of the flux of triad in loop quantum gravity, namely the fundamental and alternative flux operators. In parallel to the consistency check on the two versions of operator by the algebraic calculus in the literature, we check their consistency by the graphical calculus. Our calculation based on the original Brink graphical method is obviously simpler than the algebraic calculation. It turns out that our consistency check fixes the regulating factor $\kappa_{\rm reg}$ of the Ashtekar-Lewandowski volume operator as $\frac12$, which corrects its previous value in the literature.