Testing quantum theory with thought experiments

TL;DR

This paper reviews advanced quantum thought experiments involving observers, such as Wigner's friend and Frauchiger-Renner, to explore foundational questions and interpretational issues in quantum mechanics.

Contribution

It provides a comprehensive overview of quantum thought experiments, clarifying their significance and addressing criticisms to deepen understanding of quantum foundations.

Findings

Clarifies the interpretational significance of key thought experiments

Addresses objections and criticisms of quantum thought experiments

Highlights the role of thought experiments in understanding quantum foundations

Abstract

Quantum mechanics is one of our most successful physical theories; its predictions agree with experimental observations to an extremely high accuracy. However, the bare formalism of quantum theory does not provide straightforward answers to seemingly simple questions: for example, how should one model systems that include agents who are themselves using quantum theory? These foundational questions may be investigated with a theorist's tool -- the thought experiment. Its purpose is to turn debates about the interpretation of quantum theory into actual physics questions. In this article, we give a state-of-the-art overview on quantum thought experiments involving observers, from the basic Wigner's friend to the recent Frauchiger-Renner setup, clarifying their interpretational significance and responding to objections and criticism on the way.