Bell nonlocality in networks

TL;DR

This paper reviews the development of Bell nonlocality in networks, highlighting new phenomena, methods, and challenges arising from complex quantum experiments involving multiple sources and parties.

Contribution

It provides a comprehensive overview of the main concepts, methods, and recent results in the emerging field of Bell nonlocality in quantum networks.

Findings

Identification of new nonlocal phenomena in network scenarios

Development of methods to analyze network nonlocal correlations

Discussion of future challenges in quantum network nonlocality

Abstract

Bell's theorem proves that quantum theory is inconsistent with local physical models. It has propelled research in the foundations of quantum theory and quantum information science. As a fundamental feature of quantum theory, it impacts predictions far beyond the traditional scenario of the Einstein-Podolsky-Rosen paradox. In the last decade, the investigation of nonlocality has moved beyond Bell's theorem to consider more sophisticated experiments that involve several independent sources which distribute shares of physical systems among many parties in a network. Network scenarios, and the nonlocal correlations that they give rise to, lead to phenomena that have no counterpart in traditional Bell experiments, thus presenting a formidable conceptual and practical challenge. This review discusses the main concepts, methods, results and future challenges in the emerging topic of Bell nonlocality in networks.