A quintet of quandaries: five no-go theorems for Relational Quantum Mechanics

TL;DR

This paper presents five no-go theorems demonstrating fundamental limitations of Relational Quantum Mechanics, challenging its claims of universality and completeness by showing inherent contradictions in its core assumptions.

Contribution

It introduces five no-go theorems that reveal critical inconsistencies in Relational Quantum Mechanics, questioning its foundational claims.

Findings

Five no-go theorems show RQM cannot fully uphold its core principles

Relational facts and quantum events face fundamental logical constraints

Challenges to the universality and completeness of RQM

Abstract

Relational quantum mechanics (RQM) proposes an ontology of relations between physical systems, where any system can serve as an `observer' and any physical interaction between systems counts as a `measurement'. Quantities take unique values spontaneously in these interactions, and the occurrence of such `quantum events' is strictly relative to the observing system, making them `relative facts'. The quantum state represents the objective information that one system has about another by virtue of correlations between their physical variables. The ontology of RQM thereby strives to uphold the universality and completeness of quantum theory, while at the same time maintaining that the actualization of each unique quantum event is a fundamental physical event. Can RQM sustain this precarious balancing act? Here we present five no-go theorems that imply it cannot; something has to give way.