Relational Quantum Mechanics and the PBR Theorem: A Peaceful Coexistence

Abstract

According to Relational Quantum Mechanics (RQM) the wave function $\psi$ is considered neither a concrete physical item evolving in spacetime, nor an object representing the absolute state of a certain quantum system. In this interpretative framework, $\psi$ is defined as a computational device encoding observers' information; hence, RQM offers a somewhat epistemic view of the wave function. This perspective seems to be at odds with the PBR theorem, a formal result excluding that wave functions represent knowledge of an underlying reality described by some ontic state. In this paper we argue that RQM is not affected by the conclusions of PBR's argument; consequently, the alleged inconsistency can be dissolved. To do that, we will thoroughly discuss the very foundations of the PBR theorem, i.e. Harrigan and Spekkens' categorization of ontological models, showing that their implicit assumptions about the nature of the ontic state are incompatible with the main tenets of RQM. Then, we will ask whether it is possible to derive a relational PBR-type result, answering in the negative. This conclusion shows some limitations of this theorem not yet discussed in the literature.

References in corpus (17)

• Relational Quantum Mechanics
• On the reality of the quantum state
• Quantum probabilities as Bayesian probabilities
• Einstein, incompleteness, and the epistemic view of quantum states
• How Quantum Mechanics can consistently describe the use of itself
• Quantum theory cannot consistently describe the use of itself
• Is the quantum state real? An extended review of $\psi$-ontology theorems
• A strong no-go theorem on the Wigner's friend paradox
• Relational EPR
• Distinct Quantum States Can Be Compatible with a Single State of Reality
• Implications of the Pusey-Barrett-Rudolph quantum no-go theorem
• "Space is blue and birds fly through it"
• An argument against the realistic interpretation of the wave function
• No-go theorem for the composition of quantum systems
• The Bundle Theory Approach to Relational Quantum Mechanics
• Reality of the quantum state: Towards a stronger ψ-ontology theorem
• Reflections on the PBR Theorem: Reality Criteria & Preparation Independence

Cited by in corpus (6)

• On the reality of the quantum state once again: A no-go theorem for $\psi$-ontic models
• Relational Quantum Mechanics and Contextuality
• Is the Statistical Interpretation of Quantum Mechanics $\psi$-Ontic or $\psi$-Epistemic?
• The Relational Interpretation of Quantum Physics
• Information versus Physicality: On the Nature of the Wavefunctions of Quantum Mechanics
• Can the ontology of Bohmian mechanics consists only in particles? The PBR theorem says no