Time-dependent Nonequilibrium Thermodynamics: A Master-equation Approach

Master equation could be applied to model various kinds of biochemical systems. A general theory for its time-dependent nonequilibrium thermodynamics is rigorously derived. We not only introduce a concept of general internal energy, but also propose an extension of the equilibrium state. Moreover, we find out an explicit expression for the extended form of the Second Law, which is phenomenologically stated as "the conversion of work to excess heat is irreversible". The theory is carefully applied to several thermodynamic processes, and its consistence with the classical thermodynamics is clearly shown.