Negative friction and mobilities induced by friction fluctuation

Area of Science:

• Nonlinear physics
• Statistical mechanics
• Condensed matter physics

Background:

• Brownian motion is fundamental to understanding particle dynamics in various systems.
• Transport phenomena in periodic potentials are crucial for nanoscale devices and material science.
• Friction and its fluctuations significantly influence particle movement and system behavior.

Purpose of the Study:

• To investigate the transport phenomena of an inertial Brownian particle in a symmetric, periodic potential.
• To analyze the effects of deterministic dynamics and friction coefficient fluctuations on particle transport.
• To explore the emergence of negative friction and anomalous mobilities under varying conditions.

Main Methods:

• Analysis of deterministic dynamics and friction coefficient fluctuations.
• Investigation of particle transport driven by time-periodic and constant bias forces.
• Utilizing basins of attraction to understand underlying physical mechanisms.
• Examining probability distributions of particle velocity and diffusion coefficients.

Main Results:

• Deterministic case: Negative friction and diverse mobilities (absolute, differential negative, giant positive) observed with varying friction coefficients.
• Fluctuating friction: Can enhance, weaken, or eliminate transport phenomena.
• Small fluctuations: Lead to negative friction, absolute negative mobility, superdiffusion, and ballistic diffusion.
• Large fluctuations: Cause all observed phenomena to vanish.

Conclusions:

• Friction coefficient fluctuations play a critical role in modulating particle transport, leading to complex behaviors like negative friction and anomalous diffusion.
• The findings highlight the potential for controlling particle transport in materials by manipulating friction.
• The study suggests broad applicability in materials with varying defects, strains, or compositions, indicating the prevalence of tunable friction effects.