Emergence of Spacetime from Structural Interpretations

Why is Spacetime’s atom not Spacetime itself?

Abstract

In recent discussions as to emergence of spacetime, spacetime is said to be not fundamental in quantum regions, which we must apply quantum gravity’s theory to and to be derived from fundamental entities. This is a very strange picture not only from philosophically but also commonsensically. As to classical regions, there have been already many discussions from structural realists about spacetime in General Relativity regarding how “curved spacetime” exists and where it does. But most papers on emergence of spacetime in quantum gravity’s theory are independent from details of these structural interpretations, namely traditional discussions about ontology of spacetime. This paper tries to connect classical structural spacetime and quantum spacetime’s atoms called “spinnetwork” in loop quantum gravity as one of the examples of fundamental entities through the quantization of gravitational fields. And I check from ontological viewpoints whether there are some structural discontinuities between classical and quantum regions based on “isomorphism”, comparing the quantization of electromagnetic fields.