Phase Diagram and Scaling of Granular Materials under Horizontal Vibrations

Horizontal vibration of a granular material is studied experimentally and by means of molecular dynamics simulations. We focus on the transition from a more solidlike behavior of the granulate, which is obtained at small driving velocities, to a more fluidlike behavior for higher velocities. We present two different order parameters suitable to characterize the transition, namely the granular temperature and the pair distribution function. When using different frequencies f and amplitudes A₀ of the vibration, we find that the transition point from the solid to the fluid phase scales with A₀f², whereas the granular temperature scales as (A₀f)1.66.