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Bibliographic Details
Main Authors: Guan, Vincent, Atanackovic, Lazar, Neklyudov, Kirill
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.08550
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author Guan, Vincent
Atanackovic, Lazar
Neklyudov, Kirill
author_facet Guan, Vincent
Atanackovic, Lazar
Neklyudov, Kirill
contents The population dynamics of molecules, cells, and organisms are governed by a number of unknown forces. In the last decade, population dynamics have predominantly been modeled with Wasserstein gradient flows. However, since gradient flows minimize free energy, they fail to capture important dynamical properties, such as periodicity. In this work, we propose a change in perspective by considering dynamics that minimize a population-level action under a damped Wasserstein Lagrangian. By deriving the corresponding Hamiltonian equations of motion, we formalize Wasserstein Lagrangian Mechanics, a structured class of second-order dynamics that encompasses classical mechanics, quantum mechanics, and gradient flows. We then propose WLM as the first algorithm that learns these second-order dynamics from observed marginals, without specifying the Lagrangian. By directly learning the population mechanics, WLM can both forecast and interpolate unseen marginals, and outperforms existing gradient flow and flow matching methods across a wide range of dynamics, including vortex dynamics, embryonic development, and flocking.
format Preprint
id arxiv_https___arxiv_org_abs_2605_08550
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Call to Lagrangian Action: Learning Population Mechanics from Temporal Snapshots
Guan, Vincent
Atanackovic, Lazar
Neklyudov, Kirill
Machine Learning
49S05 (Primary) 49Q22, 35Q70 (Secondary)
The population dynamics of molecules, cells, and organisms are governed by a number of unknown forces. In the last decade, population dynamics have predominantly been modeled with Wasserstein gradient flows. However, since gradient flows minimize free energy, they fail to capture important dynamical properties, such as periodicity. In this work, we propose a change in perspective by considering dynamics that minimize a population-level action under a damped Wasserstein Lagrangian. By deriving the corresponding Hamiltonian equations of motion, we formalize Wasserstein Lagrangian Mechanics, a structured class of second-order dynamics that encompasses classical mechanics, quantum mechanics, and gradient flows. We then propose WLM as the first algorithm that learns these second-order dynamics from observed marginals, without specifying the Lagrangian. By directly learning the population mechanics, WLM can both forecast and interpolate unseen marginals, and outperforms existing gradient flow and flow matching methods across a wide range of dynamics, including vortex dynamics, embryonic development, and flocking.
title A Call to Lagrangian Action: Learning Population Mechanics from Temporal Snapshots
topic Machine Learning
49S05 (Primary) 49Q22, 35Q70 (Secondary)
url https://arxiv.org/abs/2605.08550