Enhanced diffusion over a periodic trap by hydrodynamic coupling to an elastic mode.

Area of Science:

• Soft Matter Physics
• Colloidal Science
• Biophysics

Background:

• Hydrodynamic forces couple degrees of freedom in physical systems, even without Hamiltonian interactions.
• Microscopic particle transport near deformable boundaries is a widespread phenomenon, but elastohydrodynamic couplings' effects on Brownian motion are not well understood.
• Experimental monitoring of small surface deformations alongside particle motion is challenging due to disparate temporal and spatial scales.

Purpose of the Study:

• To investigate the influence of elastohydrodynamic couplings on Brownian motion.
• To develop a minimal model for hydrodynamic coupling between a colloidal particle and a fluctuating elastic mode near a deformable boundary.
• To quantify the impact of surface compliance on particle transport.

Main Methods:

• Development of a minimal theoretical model.
• Simulation of a colloidal particle coupled to a fluctuating elastic mode.
• Analysis of particle diffusion in the presence of an external periodic potential.

Main Results:

• The late-time diffusion coefficient of the colloidal particle increases with the compliance of the elastic mode.
• Demonstrated that soft boundaries can significantly affect spontaneous microscopic transport.
• Showed that effects of fast, small surface deformations are imprinted in long-term colloidal mobility.

Conclusions:

• Elastohydrodynamic couplings play a crucial role in microscopic particle transport near soft boundaries.
• This study quantifies the impact of surface compliance on particle diffusion, with implications for nanoscale and biological physics.
• The findings suggest that subtle surface dynamics are measurable through colloidal mobility, offering new experimental avenues.