The Informational Observer in Relational Quantum Mechanics

Abstract

Relational Quantum Mechanics (RQM) treats quantum states as observer-dependent facts rather than absolute properties. While this relational stance is conceptually attractive, it raises concerns about empirical confirmation, particularly in multi-observer scenarios. Existing responses within RQM focus on securing agreement between observers by strengthening the status, stability, or accessibility of recorded outcomes. However, they leave open a more basic question: what grounds the persistence of an observer across time? Scientific observation presupposes stable records and the capacity to relate outcomes across successive measurements. We argue that the minimal definition of the observer in RQM as a merely interacting physical system is insufficient to support this requirement. We propose a complementary account of the observer that distinguishes physical interaction from informational coherence, and show how this distinction supports empirical confirmation in Wigner's friend-type scenarios.

arXiv comment30 pages, 1 figure

References in corpus (35)

• Relational Quantum Mechanics
• Informational derivation of Quantum Theory
• Characterizing quantum theory in terms of information-theoretic constraints
• How Quantum Mechanics can consistently describe the use of itself
• Quantum theory cannot consistently describe the use of itself
• Direct measurement of general quantum states using weak measurement
• Amplification of Angular Rotations Using Weak Measurements
• A strong no-go theorem on the Wigner's friend paradox
• Weak value amplification is suboptimal for estimation and detection
• Precision metrology using weak measurements
• Continuous weak measurement of quantum coherent oscillations
• Quantum Cheshire Cats
• The past of a quantum particle
• A no-go theorem for observer-independent facts
• How the result of a single coin toss can turn out to be 100 heads
• Measuring ultrasmall time delays of light by joint weak measurements
• When amplification with weak values fails to suppress technical noise
• Sequential weak measurement
• Weak value controversy
• Weak value beyond conditional expectation value of the pointer readings
• Relational Quantum Mechanics is about Facts, not States: A reply to Pienaar and Brukner
• Power-recycled weak-value-based metrology
• Tracing the past of a quantum particle
• Observing angular deviations in light beam reflection via weak measurements
• The Case of the Disappearing (and Re-Appearing) Particle
• Stable Facts, Relative Facts
• A New Class of Retrocausal Models
• Weak-Value Amplification of light deflection by a dark atomic ensemble
• Weak values and quantum properties
• Weak-value amplification: state of play
• On the novelty, efficacy, and significance of weak measurements for quantum tomography
• Can Two Quantum Cheshire Cats Exchange Grins?
• Achieving metrological precision limits through post-selection
• Photons are lying about where they have been, again
• Weak Particle Presence