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Resonant Diffusion of a Gravitactic Circle Swimmer
Oleksandr Chepizhko1, Thomas Franosch1
1Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21A, A-6020 Innsbruck, Austria.
Physical Review Letters
|December 9, 2022
Summary
We found that a chiral active particle
Area of Science:
- Physics of active matter
- Statistical mechanics
- Non-equilibrium systems
Background:
- Chiral active particles exhibit complex dynamics under external fields.
- Gravitaxis influences particle orientation and motion.
- Understanding particle transport is crucial for active matter systems.
Purpose of the Study:
- To investigate the dynamics of a single chiral active particle under gravitational torque.
- To analyze the influence of external torque on particle diffusivity.
- To provide analytical descriptions for particle transport phenomena.
Main Methods:
- Computer simulations of particle dynamics.
- Derivation of analytic expressions for mean-square displacement.
- Analysis of Fokker-Planck equation for angular motion.
Main Results:
- Simulations show a significant increase in long-time diffusivity near resonance.
- Analytic expressions reveal the role of eigenvalues in enhanced diffusion.
- A pronounced maximum in diffusivity is observed as external torque approaches intrinsic angular drift.
Conclusions:
- The study rationalizes enhanced diffusivity through vanishing eigenvalues of the Fokker-Planck equation.
- A harmonic-oscillator model quantitatively describes resonance onset.
- The findings elucidate the transition to critical-fluctuation-dominated regimes in active particle systems.
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