Acoustic waves propagating in composite-particle gases under uniform gravitational fields

Abstract

The quantum discrete kinetic equations are solved to study the propagation of plane waves in a system of composite particles under the magnetic field which is subjected to the Beltrami field condition and particles being also under uniform external gravitational field. We compare the dispersion relations thus obtained by the relevant Pauli-blocking factor $\ensuremath{\theta}$ which describes the different-statistics particles for the quantum analog of the discrete Boltzmann system when $\ensuremath{\theta}$ is positive (say, $\ensuremath{\theta}=1$ for Bose gases), zero (Boltzmann gases), and negative ($\ensuremath{\theta}=\ensuremath{-}1$ for Fermi Gases). We found, as the effect of magnetic field being zero (using the Beltrami field condition), the gravitational field effect will induce anomalous dispersion relations (e.g., negative sound speed).