CRC Press eBooks

Quantum Gases

Teunis C. Dorlas

Published Mar 2, 2021• 0 citations

Abstract

When identical particles are not localized they can no longer be distinguished . This situation occurs in the case of a gas since the particles of a gas are unconstrained in their motion except by the walls of the container. It also occurs when the particles are so close together that their wave functions overlap, that is when they are free to exchange positions. It should be stressed that this is a typical quantum-mechanical phenomenon, formulated as QM 3. Classical particles are always distinguishable because one can in principle follow each particle along its trajectory. According to quantum mechanics this is impossible even in principle. According to principle QM 3, there are in fact two different kinds of statistics depending on the type of particle: Bose-Einstein statistics for bosons and Fermi-Dirac statistics for fermions . This is related to the fact that fermions satisfy the Pauli exclusion principle ; there can be no more than one particle in each eigenstate.

DOI: 10.1201/9781003037170-27

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