Overdamped limits for Langevin dynamics with position-dependent coefficients via $L^2$-hypocoercivity

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Auteur principal: Blassel, Noé
Format: Preprint
Publié: 2026
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author Blassel, Noé
author_facet Blassel, Noé
contents This note provides a simple derivation of the overdamped approximation for kinetic (or underdamped) equilibrium Langevin dynamics, in cases where certain coefficients depend on the position variable. The equivalent small-mass limit of these dynamics, known as the Kramers--Smoluchowski approximation, in the case of a state-dependent friction coefficient, has been previously studied by a variety of approaches. Our new approach uses hypocoercivity estimates, which may be of interest in their own right, and lead to a very direct derivation, providing in particular a clear explanation of the ``noise-induced drift'' term in the overdamped equation in the case of a state-dependent friction term. Using the same approach, we also treat effective kinetic dynamical models derived from a coarse-graining approximation of a high-dimensional system, as well as a class of kinetic dynamics with position-dependent mass matrices. All of these models are relevant to applications in computational chemistry. We finally identify a mistake in a related work, and suggest a solution.
format Preprint
id arxiv_https___arxiv_org_abs_2602_16924
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Overdamped limits for Langevin dynamics with position-dependent coefficients via $L^2$-hypocoercivity
Blassel, Noé
Probability
Statistical Mechanics
Mathematical Physics
This note provides a simple derivation of the overdamped approximation for kinetic (or underdamped) equilibrium Langevin dynamics, in cases where certain coefficients depend on the position variable. The equivalent small-mass limit of these dynamics, known as the Kramers--Smoluchowski approximation, in the case of a state-dependent friction coefficient, has been previously studied by a variety of approaches. Our new approach uses hypocoercivity estimates, which may be of interest in their own right, and lead to a very direct derivation, providing in particular a clear explanation of the ``noise-induced drift'' term in the overdamped equation in the case of a state-dependent friction term. Using the same approach, we also treat effective kinetic dynamical models derived from a coarse-graining approximation of a high-dimensional system, as well as a class of kinetic dynamics with position-dependent mass matrices. All of these models are relevant to applications in computational chemistry. We finally identify a mistake in a related work, and suggest a solution.
title Overdamped limits for Langevin dynamics with position-dependent coefficients via $L^2$-hypocoercivity
topic Probability
Statistical Mechanics
Mathematical Physics
url https://arxiv.org/abs/2602.16924