The Pedagogical Model of Quantum Mechanics over Sets

Abstract

This paper develops a simplified pedagogical or toy model of (finite-dimensional non-relativistic) quantum mechanics (QM). The model uses vector spaces over \(\mathbb{Z}_{2}=\{0,1\}\), where the \(0,1\)-vectors can also be interpreted as sets, so the model is "quantum mechanics over sets" or QM/Sets. At the level of sets, the key notion is that of a partition or, equivalently, an equivalence relation. Partitions are the logical-level notions to model distinctions versus indistinctions, definiteness versus indefiniteness, or distinguishability versus indistinguishability. Those pairs of concepts are the key to understanding the non-classical 'weirdness' of QM. The key non-classical notion in QM is the notion of superposition, i.e., the notion of a state that is indefinite between two or more definite- or eigen-states. As Richard Feynman emphasized, all the weirdness of QM is illustrated in the double-slit experiment so the QM/Sets version is used to make the key points. The simplified model provides an explanation and intuitive picture to answer the key question: "How can the particle get to the detection wall without passing through one slit or the other?"