Fermi statistics of weakly excited granular materials in a vibrating bed: molecular dynamics simulations

Molecular dynamics simulations were carried out to test the thermodynamic t heory of weakly excited, two-dimensional, granular systems [Hayakawa and Ho ng, Phys. Rev. Lett. 78 (1997) 2764], where granular materials are viewed a s a collection of spinless Fermions. We first determine the global temperat ure T by fitting the steady-state density profile to the Fermi distribution function, and then measure the center of mass, (z(T)], and its fluctuation s, [(Delta z(T))(2)] as a function of T. We find a fairly good agreement be tween theory and simulations, in particular, in the estimation of the tempe rature and the scaling behavior of (z(T)) and ((Delta z(T))(2)]. (C) 1999 P ublished by Elsevier Science B.V. All rights reserved.