Fermi statistics applied to a weakly excited column of granular particles in a vibrating bed

A one-dimensional experiment in granular dynamics is carried out to test the thermodynamic theory of weakly excited granular systems [Hayakawa and Hong, Phys. Rev. Lett. 78 (1997) 2764] where granular particles are treated as spinless Fermions. The density profile is measured and then fit to a granular Fermi distribution function, from which the global temperature of the system, T, is determined. Then the center of mass, z(T) , and its fluctuations, Δz(T)2 , are measured and plotted as functions of T. The granular Fermi function fits the density profile fairly well, with the value of T being reasonably close to the predicted value. The scaling behavior of z(T) and Δz(T)2 is in excellent agreement with the theory.