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Decomposition of force fluctuations far from equilibrium.
Kumiko Hayashi1, Shin-Ichi Sasa
1Department of Pure and Applied Sciences, University of Tokyo, Komaba, Tokyo 153-8902, Japan.
Summary
A simple condition dictates how forces decompose in nonequilibrium Langevin systems. This leads to a universal inequality relating diffusion, mobility, friction, and temperature in systems far from equilibrium.
Area of Science:
- Statistical physics
- Non-equilibrium thermodynamics
- Soft matter physics
Background:
- Understanding the behavior of systems far from equilibrium is crucial in various scientific fields.
- Coarse-graining is a common technique to simplify complex systems.
- Decomposing forces in these systems is essential for theoretical analysis.
Purpose of the Study:
- To identify a simple condition for the decomposition of coarse-grained forces in a nonequilibrium Langevin system.
- To derive a universal inequality relating key physical parameters.
- To explore the applicability of this decomposition to a broader range of systems.
Main Methods:
- Study of a nonequilibrium Langevin system.
- Derivation of a universal inequality based on a force decomposition condition.
Main Results:
- A simple condition was found to determine the decomposition of coarse-grained force into dissipative force, effective driving force, and noise.
- A universal inequality, D >= gamma * mu(d)^2 * T, was derived, connecting diffusion constant (D), differential mobility (mu(d)), bare friction constant (gamma), and temperature (T).
Conclusions:
- The identified force decomposition condition is simple and general.
- The derived inequality provides a fundamental relationship between key parameters in nonequilibrium systems.
- The proposed decomposition method is expected to be applicable to a wide variety of systems operating far from equilibrium.