Colossal Brownian yet non-Gaussian diffusion induced by nonequilibrium noise.

Area of Science:

• Statistical Physics
• Complex Systems

Background:

• Brownian motion typically exhibits Gaussian statistics.
• Non-Gaussian diffusion is observed in various complex systems.
• Existing models often rely on space- or time-dependent diffusivity.

Purpose of the Study:

• To investigate a novel mechanism for non-Gaussian diffusion.
• To characterize diffusion behavior induced by external nonthermal noise in a periodic potential.
• To explore the implications for particle transport and first arrival problems.

Main Methods:

• Analysis of particle trajectories under external nonthermal noise.
• Characterization of mean square displacement (MSD) and probability density functions (PDFs).
• Comparison of diffusion statistics with standard Brownian motion and

Main Results:

• Observed linear growth of MSD with time, characteristic of Brownian motion.
• Identified Gaussian-like spreading but with an exponentially decaying tail in position increment PDFs.
• Demonstrated that this behavior arises from external nonthermal noise, not altered diffusivity.
• Reported a colossal enhancement of diffusion, exceeding previously known

Conclusions:

• External nonthermal noise in periodic potentials can drive anomalous diffusion with unique statistical properties.
• The exponential tail in increment statistics leads to significantly enhanced diffusion rates.
• This finding has broad implications for understanding transport phenomena, including diffusion-limited reactions in biological systems.