From Quantum to Classical Physics: The Role of Distinguishability

Abstract

The transition from quantum to classical statistics is studied in light of Huggett's finding that the empirical data do not support the usual claim that the distinction between classical and quantum objects consists in the capacity of classical objects to carry permutable labels as opposed to quantum objects. Since permutation of the labels of classical objects counts as a distinct configuration, this feature is usually taken as signifying that classical objects are not identical while quantum objects are. Huggett's finding threatens that characterization of the distinction between classical and quantum objects. The various statistical distributions are examined, and it is found that other distinctions, corresponding to separability and distinguishability, emerge in the classical limit. The role of the chemical potential (the rate of change of the Helmholtz free energy with particle number) is found to be of crucial significance in characterizing this emergence of classicality from the quantum distributions.