Thermodynamics of the harmonic oscillator using coherent states

– The ongoing discussion whether thermodynamic properties can be extracted from a (possibly approximate) quantum mechanical time evolution using time averages is fed with an instructive example. It is shown for the harmonic oscillator how the Hilbert space or an appropriately defined phase space must be populated in terms of coherent states in order to obtain the quantum result respectively the classical one. Introduction. – Transport models which employ wave packet dynamics are widely used in atomic, solid state and nuclear physics today. Examples range from the description of hydrogen plasmas [1] over the investigation of critical properties of noble gases [2] to simulations of heavy ion collisions in nuclear physics [3, 4, 5]. In all of these models the quantum mechanical time evolution is approximated by the evolution of a (possibly antisymmetrized) product state composed of Gaussian single-particle wave packets (squeezed coherent states [6])