Measuring Quantum Superpositions (Or, “It is only the theory which decides what can be observed.”)

CHRISTIAN DE RONDE

Non-reflexive logics, non-individuals, and the philosophy of quantum mechanics: Essays in honor of the philosophy of Décio Krause.

Springer

Año: 2021; p. 1 - 25

In this work we attempt to confront the orthodox widespread claim present in the foundational literature of Quantum Mechanics (QM) according to which ‘superpositions are never actually observed in the lab’. In order to do so, we begin by providing a critical analysis of the famous measurement problem which, we will argue, was originated by the strict application of the empirical-positivist requirements to subsume the quantum formalism under their specific understanding of ‘theory’. In this context, the ad hoc introduction of the projection postulate (or measurement rule) can be understood as a necessary requirement coming from a naive empiricist standpoint which presupposes that observations are self evident givens of “common sense” experience —independent of metaphysical (or conceptual) presuppositions— yet necessarily represented in binary terms. We then turn our attention to two “non-collapse” interpretations of QM —namely, modal and many worlds— which even though deny that the “collapse” is a real physical process anyhow retain the measurement rule as a necessary constituent of the theory. In contraposition, following Einstein’s claim according to which “it is only the theory which decides what can be observed”, we propose a return to the realist representational understanding of physical theories in which ‘observation’ is not a “self evident” given of experience but something that can be only understood in the context of theoretical (formal-conceptual) presuppositions. It is from this standpoint that we discuss a new non-classical conceptual representation which allows us to understand quantum phenomena in an intuitive (anschaulicht) manner. Leaving behind the projection postulate, we discuss the general physical conditions for measuring and observing quantum superpositions.