Causal Fermion Systems: Spacetime as the web of correlations of a many-body quantum system

Abstract

In this paper, we argue that spacetime in causal fermion systems can be understood as the web of correlations of a many-body quantum system.This argument highlights the fact that causal fermion systems is a completely relational theory. We also explain how our perception of a background (spacetime) emerges in the limit where the number of states taken in consideration goes to infinity. This thereby constitutes a complete viable ontology for causal fermion systems which are not reliant on the continuum limit. A key insight is the fact that in a relevant subset of causal fermion systems, which includes the continuum limit of the Minkowski vacuum spacetime, minimization of the causal action can be understood as a minimization of fluctuations in the causal structure of spacetime.