Strong-chaos-caused negative mobility in a periodic substrate potential

Area of Science:

• Nonlinear dynamics
• Statistical physics
• Condensed matter physics

Background:

• Anomalous transport phenomena challenge classical understanding of particle motion.
• Negative mobility, where particles move against the applied force, is a key area of interest.
• Understanding particle behavior in complex potentials is crucial for designing novel devices.

Purpose of the Study:

• To numerically investigate negative mobility in an inertial Brownian particle.
• To explore the influence of periodic forces, bias, and noise on particle mobility.
• To elucidate the connection between chaotic attractors and negative mobility.

Main Methods:

• Numerical simulations of an inertial Brownian particle in a periodic double-well potential.
• Analysis of average velocity, bifurcation diagrams, and maximal Lyapunov exponents.
• Investigation of noise effects (intensity and correlation time) and attractor dynamics (time series, phase-space maps, power spectra).

Main Results:

• Deterministic case: varying parameters and forces induce negative, differential negative, and giant positive mobilities, linked to chaos.
• Noise effects: intensity can enhance or cause mobilities; correlation time modulates these effects.
• Mechanism: Strong Chaotic Attractors (SCAs) are identified as the cause of negative mobility, unlike other attractors.

Conclusions:

• Chaos and noise significantly impact particle mobility, enabling negative mobility under specific conditions.
• Strong Chaotic Attractors provide a mechanism for observing negative mobility.
• Findings have potential applications in areas like atomic chains and superconducting devices.