Protective measurements and the PBR theorem

TL;DR

Protective measurements offer new experimental ways to test quantum mechanics, showing that a quantum state describes a single system and supporting the PBR theorem's assertion of the reality of quantum states.

Contribution

This paper connects protective measurements with the PBR theorem, highlighting how they jointly support the ontological reality of quantum states.

Findings

Protective measurements demonstrate a quantum state describes a single system.

They anticipate the PBR theorem's implications.

Support for the reality of quantum states.

Abstract

Protective measurements illustrate how Yakir Aharonov's fundamental insights into quantum theory yield new experimental paradigms that allow us to test quantum mechanics in ways that were not possible before. As for quantum theory itself, protective measurements demonstrate that a quantum state describes a single system, not only an ensemble of systems, and reveal a rich ontology in the quantum state of a single system. We discuss in what sense protective measurements anticipate the theorem of Pusey, Barrett, and Rudolph (PBR), stating that, if quantum predictions are correct, then two distinct quantum states cannot represent the same physical reality.