Foundations of quantum mechanics: measurement and interpretation

Investigate and clarify foundational issues in quantum mechanics related to the measurement problem, the interpretation of quantum states, and the nature of physical reality, aiming for experimentally testable and conceptually coherent resolutions.

Background

Chad Orzel broadens the discussion of new physics beyond particle physics to emphasize unresolved foundational questions about quantum measurement, interpretations, and reality. He highlights emerging experimental platforms—such as cavity optomechanics and quantum computing—that may enable tests bearing on these issues.

These questions remain central to understanding quantum theory’s implications and limits, and progress may come from both conceptual advances and new experiments.

References

Some of the deepest open questions in physics concern not fundamental particles, but the foundations of quantum mechanics: issues of measurement, and interpretation, and the nature of reality [65].

— The sounds of science a symphony for many instruments and voices part II  (2404.11724 - Hooft et al., 2024) in Section 8: Will there be new physics? We're not done with the old physics yet

Which of these two statistical interpretations provides the appropriate physical description is ultimately an empirical question to be decided by experiment.

— The Unidirectional Current as First Arrival-Time POVM: An MS-Kijowski Identity, Physical Interpretation, and Mathematical Applications  (2608.16510 - Marchewka, 17 Aug 2026) in Section 4, subsection “From the MS Hazard Law to a Generalized Born-Rule Interpretation”; reiterated in Section 6, Conclusion

We can next pose the most natural question: what does it mean to make an observation? and as much incredible that it may sound, we still do not have an answer for that.

— Quantum observables as Fréchet sensitivity kernels  (2608.23191 - Abreu, 24 Aug 2026) in Introduction

However, because each individual world-branch looks no more or less nonlocal than the world according to textbook quantum theory, it is not clear whether the Everett interpretation's dynamical locality is more than a metaphysical statement, nor is it easy to discern what concrete benefits it truly provides.

— The Stochastic-Quantum Correspondence  (2302.10778 - Barandes, 2023) in Section Discussion and Future Work, paragraph comparing the stochastic-quantum correspondence with the Everett interpretation

One of its open problems is the preferred basis problem: if $|\Psi\rangle$ denotes the global wave function of the Universe, how should one decompose it into different branches that correspond to different worlds (like ours) with observers inside it?

— Redundant Records of the Past: Unifying Quantum Darwinism and Decoherent Histories  (2610.09845 - Strasberg, 7 Oct 2026) in Section 5.2, “Multiple events”