Evolutionary strategy for inverse charge measurements of dielectric particles

TL;DR

This paper introduces an evolutionary optimization method to accurately infer dielectric particle charges from observed trajectories, accounting for complex electrostatic and polarization effects, demonstrated on free-falling charged granular particles.

Contribution

The paper presents a novel computational strategy using evolutionary algorithms to determine particle charges from trajectory data, including polarization effects and unknown initial velocities.

Findings

Accurately infers particle charges from short trajectory data.

Handles unknown initial velocities by analyzing multiple frames.

Demonstrates proof-of-concept for complex electrostatic systems.

Abstract

We report a computational strategy to obtain the charges of individual dielectric particles from experimental observation of their interactions as a function of time. This strategy uses evolutionary optimization to minimize the difference between trajectories extracted from experiment and simulated trajectories based on many-particle force fields. The force fields include both Coulombic interactions and dielectric polarization effects that arise due to particle-particle charge mismatch and particle-environment dielectric contrast. The strategy was applied to systems of free falling charged granular particles in vacuum, where electrostatic interactions are the only driving forces that influence the particles' motion. We show that when the particles' initial positions and velocities are known, the optimizer requires only an initial and final particle configuration of a short trajectory in order to accurately infer the particles' charges; when the initial velocities are unknown and only the initial positions are given, the optimizer can learn from multiple frames along the trajectory to determine the particles' initial velocities and charges. While the results presented here offer a proof-of-concept demonstration of the proposed ideas, the proposed strategy could be extended to more complex systems of electrostatically charged granular matter.