Nonequilibrium Potential Function of Chemically Driven Single Macromolecules via Jarzynski-Type Log-Mean-Exponential Work

الأصل · EN

Applying the method from recently developed fluctuation theorems to the stochastic dynamics of single macromolecules in ambient fluid at constant temperature, we establish two Jarzynski-type equalities: (1) between the log-mean-exponential (LME) of the irreversible heat dissiption of a driven molecule in nonequilibrium steady-state (NESS) and Pness(x), and (2) between the LME of the work done by the internal force of the molecule and nonequilibrium chemical potential function μness(x) ≡ U(x)+kBT Pness(x), where Pness(x) is the NESS probability density in the phase space of the macromolecule and U(x) is its internal potential function. Ψ = ∫μness(x)Pness(x)dx is shown to be a nonequilibrium generalization of the Helmholtz free energy and ΔΨ = ΔU-TΔS for nonequilibrium processes, where S =-kB∫ P(x) P(x)dx is the Gibbs entropy associated with P(x). LME of heat dissipation generalizes the concept of entropy, and the equalities define thermodynamic potential functions for open systems far from equilibrium.