Energetics of Open Systems and Chemical Potential From Micro-Dynamics Viewpoints

Abstract

We present the energetic aspect of open systems which may exchange particles with their environments. The motion of the particles is described by the classical Langevin dynamics. We study the energy balance relation among the open system and the environments along a particular realization of the stochastic process. It is clarified how much energy each particle carries when it enters or leaves the system. This energy is definitely different from the chemical potential. Then, the chemical potential is consistently interpreted from the viewpoint of energetics, paying attention to the difference of the level of description between the thermodynamics and the kinematics.