On the measurement problem in quantum mechanics: a simple proposal

TL;DR

The paper addresses the measurement problem and interpretive paradoxes in quantum mechanics. It proposes the Laboratory Physics Assumption (LPA) that restricts observables to self-adjoint operators associated with existing measuring instruments. Under this view, states appearing as mixtures when no instrument connects components are real mixtures, and the appearance of wavefunction collapse follows from the instrument structure rather than a fundamental postulate. By reframing macroscopic paradoxes and recovering collapse-like predictions without ad hoc rules, the approach offers a physically grounded interpretation in which state purity is context dependent on available observables and may evolve as experimental capabilities change.

Abstract

Some of the problems connected with the interpretation of quantum mechanics are enumerated, in particular those related to some well known paradoxes and, above all, to the measurement process. We then show how the so called "Physics Laboratory Assumption" introduced in [1], which considers as "observables'' only the self-adjoint operators corresponding to existing measuring instruments, can propose a new perspective on the aforementioned problems and can replace the wavefunction collapse postulate. [1] Luigi E. Picasso, "On the Concept of State in Quantum Mechanics: Another Way to Decoherence?'' Int. J. Theor. Phys. 62 (2), (2023)