Reconciling the Measurement Problem in Quantum Mechanics: An Einsteinian Perspective

Quantum mechanics (QM) has long been a subject of fascination and philosophical debate, largely due to its inherent non-intuitive nature. One of the most central and contentious issues in quantum theory is the measurement problem, which remains unresolved despite numerous attempts. This article delves into the measurement problem, offering a novel reconciliation using an Einsteinian approach rooted in the principles of relativity and quantum reconstruction.

The Measurement Problem in Quantum Mechanics

David Mermin has pointed out that in classical probability theory, the updating of probabilities based on new information follows a similar process to quantum mechanics (QM). However, the measurement problem arises when the quantum state vector is viewed as ontological; that is, as representing something physical in the real world. This ontological interpretation leads to a quandary known as the measurement problem, where the sudden and discontinuous update of the state vector upon measurement cannot be explained within the framework of QM as we currently understand it.

The Two Dogmas and the Measurement Problem

The root of the measurement problem, according to Bub and Pitowsky, lies in the two dogmas associated with quantum mechanics:

First Dogma: The belief that the state vector describes a physical system, dynamically evolving according to the Schr?dinger equation. Second Dogma: The belief that the state vector represents the complete description of a physical system and that any measurement outcome can be predicted with certainty based on this state.

These dogmas, underpinning much of our understanding of quantum mechanics, can lead to the measurement problem when such updates are seen as real changes in a physical system rather than updates in our knowledge of it.

A New Approach: Quantum Reconstruction Program

To address the measurement problem, a new approach emphasizes the role of Planck's constant ( h ) and the principle of relativity. According to this quantum reconstruction program, the key to reconciling the measurement problem lies not in the update of the state vector, but in the global constraints that QM imposes on the distribution of quantum events in spacetime.

A relativity-based perspective can provide a framework where the observer-independence of Planck's constant ( h )—ensured by the principles of general relativity and special relativity—becomes central. This perspective allows us to view the state vector not as a description of a single evolving system, but as part of a broader, coherent set of global constraints on quantum events. This shift in perspective helps to resolve the measurement problem by viewing the collapse of the wave function as a global, spacetime-dependent phenomenon rather than a local, discontinuous event.

Relational Quantum Mechanics and All-at-Once Explanations

The reconciliation of the measurement problem through this relativity-based approach aligns with the concept of relational quantum mechanics, where the state vector is seen as providing distributions in space and time for the outcomes of some measurement on some source. This relational view eliminates the need for a separate dynamical mechanism for the collapse of the wave function.

Furthermore, this approach is consistent with other all-at-once explanations in physics, such as:

Retrocausality: Explained by Evans, Liu, Price, and Wharton (2023). Bell Flash Ontology: Proposed by Esfeld and Gisin (2022). Superdeterminism: Advocated by Hácket Hossenfelder and Palmer (2021). Relational Quantum Mechanics: Developed by Adlam and Rovelli (2020).

By viewing QM as providing global constraints on quantum events in spacetime, the measurement problem is resolved as a non-starter. This approach not only simplifies the interpretation of quantum mechanics but also aligns with the empirical insights of relativity.

Conclusion

The measurement problem in quantum mechanics has long been a challenge, but by adopting a relativity-based perspective and reconceptualizing the role of the state vector, a coherent and intuitive framework for understanding quantum events can be developed. This approach not only resolves the measurement problem but also provides a unified picture with other concepts in modern physics. The relativity principle, by ensuring the observer-independence of Planck's constant, offers a powerful tool for reconstructing quantum mechanics in a way that is consistent with both experimental observations and theoretical principles.