This post offers a paper a wrote a few years ago for a workshop in beautiful Buenos Aires in which we explored the puzzle of distinguishability and indistinguishability in physics. Under what conditions can we consider physical objects distinguishable, and when must we assume they are indistinguishable? It turns out that a somewhat obscure quantity from statistical mechanics plays a huge role in this question: the “chemical potential” mu. The paper is a kind of tutorial on this issue, starting from some fairly elementary concepts and then going into some detail with the stat mech but hopefully in an approachable way.
The preprint version is here. Enjoy! https://arxiv.org/pdf/1707.09034
(The official citation is Kastner R. “From Quantum to Classical Physics: The Role of Distinguishability.” In: Lombardi O, Fortin S, López C, Holik F, eds. Quantum Worlds: Perspectives on the Ontology of Quantum Mechanics. Cambridge University Press; 2019:205-221.)
Transactional Interpretation 