The device-independent outlook on quantum physics (lecture notes on the power of Bell's theorem)

TL;DR

This paper introduces an operational, device-independent perspective on Bell inequalities, emphasizing their role in quantum technologies and fundamental physics, including the validation of quantum theory over classical alternatives.

Contribution

It presents a comprehensive overview of how Bell tests serve as a tool for both practical quantum applications and foundational insights, highlighting recent advances in the field.

Findings

Bell tests quantify non-classicality without detailed device knowledge

Device-independent approaches have falsified classical models

Insights gained aid in deriving quantum theory from fundamental principles

Abstract

This text is an introduction to an operational outlook on Bell inequalities, which has been very fruitful in the past few years. It has lead to the recognition that Bell tests have their own place in applied quantum technologies, because they quantify non-classicality in a device-independent way, that is, without any need to describe the degrees of freedom under study and the measurements that are performed. At the more fundamental level, the same device-independent outlook has allowed the falsification of several other alternative models that could hope to reproduce the observed statistics while keeping some classical features that quantum theory denies; and it has shed new light on the long-standing quest for deriving quantum theory from physical principles.