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Updated: May 22, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Nonequilibrium fluctuations in a driven stochastic Lorentz gas
G Gradenigo1, A Puglisi, A Sarracino
1CNR-ISC and Dipartimento di Fisica, Università Sapienza, Roma, Italy.
Summary
This study examines a driven particle system, finding that entropy production estimates align at low fields but diverge at high fields. The medium
Area of Science:
- Statistical Mechanics
- Non-equilibrium Thermodynamics
- Kinetic Theory
Background:
- Understanding non-equilibrium systems is crucial for statistical mechanics.
- Probe-particle models offer insights into complex thermodynamic behaviors.
Purpose of the Study:
- Investigate the stationary state of a driven one-dimensional kinetic model.
- Analyze the velocity distribution and entropy production estimates.
- Examine the validity of the fluctuation relation under varying external fields.
Main Methods:
- Simulated a one-dimensional kinetic model with a probe particle.
- Applied an external field (E) and particle bath at temperature (T).
- Calculated entropy production of the medium (Δs(m)) and work done by the field (W).
Main Results:
- At low external fields (E), distributions of Δs(m) and W showed good collapse and satisfied the fluctuation relation (FR).
- Both Δs(m) and W approximated total entropy production (Δs(tot)) at low fields.
- At high fields, W violated the FR, while Δs(m) continued to satisfy it.
Conclusions:
- The medium's entropy production (Δs(m)) is a robust indicator of total entropy production (Δs(tot)) in driven systems, even under strong fields.
- Work done by the external field (W) is a less reliable estimator of Δs(tot) when the fluctuation relation is violated.
- The study highlights the importance of choosing appropriate quantities to estimate entropy production in non-equilibrium statistical mechanics.
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