Time-Symmetric Current and Its Fluctuation Response Relation around Nonequilibrium Stalling Stationary State.

Area of Science:

• Stochastic thermodynamics
• Statistical mechanics
• Non-equilibrium physics

Background:

• Stochastic thermodynamics analyzes fluctuations in small systems.
• Currents are fundamental in describing thermodynamic processes.
• Time-reversal symmetry is a key concept in physics.

Purpose of the Study:

• To define a time-symmetric current in stochastic thermodynamics.
• To investigate its properties and relations to existing concepts.
• To explore its potential as an experimental tool.

Main Methods:

• Definition of the time-symmetric current using empirical measures.
• Theoretical proof of its symmetry under time reversal.
• Analysis of its ensemble average and fluctuation-response relation.

Main Results:

• The proposed time-symmetric current is invariant under time reversal.
• Its ensemble average equals the average current.
• It satisfies a modified fluctuation-response relation, even in nonequilibrium stationary states.
• This relation holds when observed currents stall.

Conclusions:

• The time-symmetric current provides a new perspective on thermodynamic currents.
• It extends the validity of fluctuation-response relations beyond equilibrium.
• It offers a practical method for experimentally determining bare transition rates.