Abstract
The notion of a thermal wave packet and the inferred spatial probability distribution are elucidated at the example of freely moving particles. Particle localisation and the use of localised Gaussian wave packets to describe a thermal state of the freely moving particle are critically assessed.
GRAPHICAL ABSTRACT
![](/cms/asset/e2a083c4-0ee8-4284-bf75-267c595dda02/tmph_a_1974110_uf0001_oc.jpg)
Disclosure statement
No potential conflict of interest was reported by the author(s).
Notes
1 According to Resolution 1 of the 26th Conference of Weights and Measures (Comptes Rendus des séances de la vingt-sixième Conférence Générale des Poids et Mesures. Résolution 1, Annexe 3, BIPM, 2019), as of 20 Mai 2019 the Boltzmann and the Planck constants have the fixed values and
, respectively.