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Updated: Apr 29, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Nonequilibrium statistical mechanics of the heat bath for two Brownian particles
Caterina De Bacco1, Fulvio Baldovin2, Enzo Orlandini2
1Laboratoire de Physique Théorique et Modéles Statistiques, CNRS et Université Paris-Sud 11, UMR8626, Bâtiment 100, 91405 Orsay Cedex, France.
Abstract:
We propose a new look at the heat bath for two Brownian particles, in which the heat bath as a "system" is both perturbed and sensed by the Brownian particles. Nonlocal thermal fluctuations give rise to bath-mediated static forces between the particles. Based on the general sum rule of the linear response theory, we derive an explicit relation linking these forces to the friction kernel describing the particles' dynamics. The relation is analytically confirmed in the case of two solvable models and could be experimentally challenged. Our results point out that the inclusion of the environment as a part of the whole system is important for micron- or nanoscale physics.
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