An argument for psi-ontology in terms of protective measurements

TL;DR

This paper presents a new proof that the quantum state is real using protective measurements within the ontological model framework, avoiding auxiliary assumptions and applying to deterministic theories.

Contribution

It provides a novel, assumption-free proof of psi-ontology using protective measurements and offers a simpler argument applicable beyond the ontological framework.

Findings

Proof of psi-ontology without auxiliary assumptions

Applicability to deterministic theories like de Broglie-Bohm

Simpler argument based on protective measurements and weaker reality criteria

Abstract

The ontological model framework provides a rigorous approach to address the question of whether the quantum state is ontic or epistemic. When considering only conventional projective measurements, auxiliary assumptions are always needed to prove the reality of the quantum state in the framework. For example, the Pusey-Barrett-Rudolph theorem is based on an additional preparation independence assumption. In this paper, we give a new proof of psi-ontology in terms of protective measurements in the ontological model framework. The proof does not rely on auxiliary assumptions, and also applies to deterministic theories such as the de Broglie-Bohm theory. In addition, we give a simpler argument for psi-ontology beyond the framework, which is only based on protective measurements and a weaker criterion of reality. The argument may be also appealing for those people who favor an anti-realist view of quantum mechanics.