The ABC of Deutsch-Hayden Descriptors

TL;DR

This paper revisits the Deutsch-Hayden descriptor formalism to clarify its role in demonstrating the locality of quantum theory, providing an accessible explanation and re-examining superdense coding within this framework.

Contribution

It offers a clear, self-contained explanation of the Deutsch-Hayden descriptors, addressing misconceptions about quantum locality and illustrating their application to superdense coding.

Findings

Descriptors demonstrate quantum locality despite entanglement

The formalism clarifies misconceptions about nonlocality in quantum theory

Superdense coding is analyzed using the descriptor approach

Abstract

It has been more than 20 years since Deutsch and Hayden proved the locality of quantum theory, using the Heisenberg picture of quantum computational networks. Of course, locality holds even in the face of entanglement and Bell's theorem. Today, most researchers in quantum foundations are still convinced not only that a local description of quantum systems has not yet been provided, but that it cannot exist. The main goal of this paper is to address this misconception by re-explaining the descriptor formalism in a hopefully accessible and self-contained way. It is a step-by-step guide to how and why descriptors work. Finally, superdense coding is revisited in the light of descriptors.