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Updated: Apr 10, 2026
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Patterning of Microorganisms and Microparticles through Sequential Capillarity-assisted Assembly
Published on: November 4, 2021
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Stochastic ratcheting of two-dimensional colloids: Directed current and dynamical transitions
Dipanjan Chakraborty1, Debasish Chaudhuri2
1Indian Institute of Science Education and Research, Mohali, Punjab 140306, India.
Summary
Colloids driven by a stochastic ratchet potential exhibit directed motion and reentrant phase transitions. Resonance in colloid current depends on ratcheting frequency and density, agreeing with analytic models.
Area of Science:
- Soft matter physics
- Statistical mechanics
- Computational physics
Background:
- Colloidal systems are model systems for studying statistical mechanics.
- Ratchet potentials can induce directed motion in systems lacking equilibrium.
Purpose of the Study:
- Investigate directed motion and phase transitions in 2D colloids driven by a stochastic ratchet.
- Analyze the influence of ratcheting frequency and density on colloid dynamics and phase behavior.
Main Methods:
- Molecular dynamics simulations of two-dimensional repulsively interacting colloids.
- Stochastic switching of a one-dimensional asymmetric and commensurate ratchet potential.
- Scaling arguments for analytic result derivation.
Main Results:
- A time-averaged directed current of colloids was observed.
- Resonance in the colloid current was found, dependent on ratcheting frequency and density.
- Nonmonotonic dependence of resonance frequency on density was identified.
- Nonequilibrium reentrant transitions between solid and modulated liquid phases occurred with increasing ratcheting frequency.
Conclusions:
- The study successfully models directed colloid motion and phase transitions using stochastic ratchets.
- Analytic results derived from scaling arguments show good agreement with simulation data.
- Nonequilibrium phenomena like reentrant transitions are observable in driven colloidal systems.
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