Restoring Locality: The Heisenberg Picture as a Separable Description of Quantum Theory

TL;DR

The work addresses the tension between local realism and quantum nonlocality by reexpressing unitary Everettian quantum theory in the Heisenberg picture, using a formal noumenal–phenomenal framework to achieve a separable, locally predictive description. It introduces relative descriptors and local branching, showing how measurement outcomes can be accounted for without action-at-a-distance, thereby reconciling Einstein locality with quantum correlations. The approach builds on Deutsch–Hayden's construction and Raymond–Robichaud's local realism, providing a rigorous mechanism for how branching occurs in localized regions (bubbles) and how correlations arise via local interactions. Overall, the paper offers a rigorous, unitary-based local realism for quantum theory, clarifying locality, branching, and the EPR paradox within a consistent Heisenberg-picture formalism.

Abstract

Local realism has been the subject of much discussion in modern physics, partly because our deepest theories of physics appear to contradict one another in regard to whether reality is local. According to general relativity, it is, as physical quantities (perceptible or not) in two spacelike separated regions cannot affect one another. Yet, in quantum theory, it has traditionally been thought that local realism cannot hold and that such effects do occur. This apparent discrepancy between the two theories is resolved by Everettian quantum theory, as first proven by Deutsch & Hayden (2000). In this paper, I will explain how local realism is respected in quantum theory and review the advances in our understanding of locality since Deutsch & Hayden's work, including the concept of local branching and the more general analysis by Raymond-Robichaud (2021)