Learning general pair interactions between self-propelled particles

Fuente: arXiv
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Main Authors: Hem, Jérôme, Poncet, Alexis, Ronceray, Pierre, Nishiguchi, Daiki, Démery, Vincent
Format: Preprint
Published: 2025
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author Hem, Jérôme
Poncet, Alexis
Ronceray, Pierre
Nishiguchi, Daiki
Démery, Vincent
author_facet Hem, Jérôme
Poncet, Alexis
Ronceray, Pierre
Nishiguchi, Daiki
Démery, Vincent
contents Synthetic active matter systems, such as active colloids, often have complex interactions, which can be of hydrodynamic, chemical or electrostatic origin and cannot be computed from first principles. Here, we use Stochastic Force Inference to learn general pair interactions, including transverse forces and torques, between self-propelled Janus particles from experimental trajectories. We use data from two experiments: one where the particles flock, and one where the system remains disordered. The learned interactions are then fed to numerical simulations, which reproduce all the experimental observables and could be extrapolated to different densities. Overall, we find that the radial interaction is mostly repulsive and isotropic, while the angular interaction has a richer angular dependence, which controls the behavior of the system; the transverse interaction is negligible. Finally, testing the symmetry relations obeyed by the inferred interactions allows us to show that they cannot come from electrostatics only, so that they must have a hydrodynamic component.
format Preprint
id arxiv_https___arxiv_org_abs_2507_13667
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning general pair interactions between self-propelled particles
Hem, Jérôme
Poncet, Alexis
Ronceray, Pierre
Nishiguchi, Daiki
Démery, Vincent
Soft Condensed Matter
Statistical Mechanics
Synthetic active matter systems, such as active colloids, often have complex interactions, which can be of hydrodynamic, chemical or electrostatic origin and cannot be computed from first principles. Here, we use Stochastic Force Inference to learn general pair interactions, including transverse forces and torques, between self-propelled Janus particles from experimental trajectories. We use data from two experiments: one where the particles flock, and one where the system remains disordered. The learned interactions are then fed to numerical simulations, which reproduce all the experimental observables and could be extrapolated to different densities. Overall, we find that the radial interaction is mostly repulsive and isotropic, while the angular interaction has a richer angular dependence, which controls the behavior of the system; the transverse interaction is negligible. Finally, testing the symmetry relations obeyed by the inferred interactions allows us to show that they cannot come from electrostatics only, so that they must have a hydrodynamic component.
title Learning general pair interactions between self-propelled particles
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2507.13667