Nonequilibrium potential function of chemically driven single macromolecules via Jarzynski-type Log-Mean-Exponential...

Area of Science:

• Statistical mechanics
• Physical chemistry
• Biophysics

Background:

• Fluctuation theorems provide powerful tools for analyzing nonequilibrium processes.
• Understanding the thermodynamics of single molecules in complex environments is crucial.
• Stochastic dynamics governs the behavior of macromolecules in fluid media.

Purpose of the Study:

• To establish new Jarzynski-type equalities for single macromolecules.
• To define nonequilibrium thermodynamic potentials for open systems.
• To generalize concepts of entropy and free energy to nonequilibrium steady states.

Main Methods:

• Application of recently developed fluctuation theorems.
• Analysis of stochastic dynamics of single macromolecules in ambient fluid.
• Derivation of equalities relating log-mean-exponential quantities to probability densities and potentials.

Main Results:

• Two Jarzynski-type equalities were established for irreversible heat dissipation and internal work.
• A nonequilibrium chemical potential function and its relation to internal potential and probability density were defined.
• A nonequilibrium generalization of Helmholtz free energy (Psi) was identified.

Conclusions:

• The derived equalities define thermodynamic potential functions for open systems far from equilibrium.
• Log-mean-exponential of heat dissipation generalizes entropy in nonequilibrium steady states.
• The study provides a framework for understanding thermodynamics in complex, driven systems.