Power-law tail of the velocity distribution in granular gases

We use a two-dimensional event-driven molecular dynamics simulation to study the velocity distribution of a granular gas. We implement the high energy injection mechanism described in Ref. [1]. At a small rate $\gamma $ we boost randomly chosen particles to a high energy. The resulting driven steady state is found to have a power-law high-energy tail in the velocity distribution, f(v) $\sim $ v $^{- \sigma }$. The simulation results for the exponent $\sigma $ are in good agreement with the theoretical predictions of Ref. [1]. \newline \newline [1] E. Ben-Naim and J. Machta, Phys. Rev. Lett. 94, 138001 (2005).