Testing quantum theory with thought experiments

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.

30 pages

References in corpus (4)

• Quantum reference frames for general symmetry groups
• Quantum information vs.\ epistemic logic: An analysis of the Frauchiger-Renner theorem
• Wigner's friend and the quasi-ideal clock
• From Copenhagen to neo-Copenhagen interpretation

Cited by in corpus (9)

• Relative Facts of Relational Quantum Mechanics are Incompatible with Quantum Mechanics
• Quantum erasing the memory of Wigner's friend
• A general quantum circuit framework for Extended Wigner's Friend Scenarios: logically and causally consistent reasoning without absolute measurement events
• Wigner and friends, a map is not the territory! Contextuality in multi-agent paradoxes
• Toys can't play: physical agents in Spekkens' theory
• From observer-dependent facts to frame-dependent measurement records in Wigner friend scenarios
• Quantum theories with local information flow
• Relative descriptors for quantum agents
• Quantum epistemology and constructivism