Liquid-Solid Phase Transition and the Change of the Frictional Force of the System with Two particles in a Box

Abstract

Liquid-solid phase transition and the change of the frictional force of a system with two hard spheres in a two-dimensional rectangular box are discussed. Under controlling the pressure or the supply of energy from the wall, the solid like state, the solid-liquid temporal coexistence state, and the liquid like state are alternatively observed. The frictional force which works on particles and the mobility of the system are measured under the supply of the energy with an asymmetric external force. Characters of frictional forces for the 0 mobility state and that for the large mobility state are obtained like, respectively, that of the static and the dynamic frictions of solid-on-solid system. The strong temperature dependency is also observed in the profile of the relation between the above frictional force and the mobility. From above results, the relation between the friction and the velocity of a plate on granular layers which includes the hysteresis loop [S.Nasuno et al.,Phys. Rev. Lett {\bf 79} (1997) 949 et. al.] is discussed.