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arXiv · 2510.27465

Snap, Crackle, and Pop: This is why the potential of mean force clashes with the fluctuation dissipation relation

Fabian Koch·Tabita Wasmer·Tanja Schilling
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Abstract

We analyze the non-linear generalized Langevin equation which contains a thermodynamic force. We show that even for systems in thermal equilibrium the presence of the thermodynamic force implies that the auto-correlation function of the fluctuating force becomes non-stationary. We further illustrate that a standard coarse-graining procedure that neglects this fact predicts waiting-time distributions incompatible with the original, microscopic process. We conclude that one needs to proceed with care when adding thermodynamic driving forces to the Langevin equation.

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Fabian Koch, Tabita Wasmer, Tanja Schilling. 2025-10-31. Snap, Crackle, and Pop: This is why the potential of mean force clashes with the fluctuation dissipation relation. https://doi.org/10.1209/0295-5075%2Fae66b4

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