title: Brownian motion in a granular gas.
abstract: The dynamics of a heavy particle in a gas of much lighter particles is studied via the Boltzmann-Lorentz equation with inelastic collisions among all particles. A formal expansion in the ratio of gas to tagged particle mass transforms the Boltzmann-Lorentz equation into a Fokker Planck equation. The predictions of the latter are tested here using direct Monte Carlo simulation of the Boltzmann-Lorentz equation. Excellent agreement is obtained for the approach to a homogeneous cooling state, the temperature of that state, approach to diffusion, and the dependence of the diffusion constant on dissipation parameters. Some results from molecular-dynamics simulations are also presented and shown to agree with the theoretical predictions.
authors.affiliation: Física Teórica, Universidad de Sevilla, E-41080 Sevilla, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Brey
authors.forename: M J
authors.initials: MJ
authors.lastname: Ruiz-Montero
authors.forename: R
authors.initials: R
authors.lastname: García-Rojo
authors.forename: J W
authors.initials: JW
authors.lastname: Dufty