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Diffusion over a fluctuating barrier in underdamped dynamics.

Jun-Wen Mao¹, Cai-Wan Shen

¹Department of Physics, Huzhou Teachers College, Huzhou 313000, People's Republic of China. jwmao@hutc.zj.cn

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|May 24, 2011

Summary

This summary is machine-generated.

We studied how particles move over changing barriers using a Langevin model. Barrier fluctuations significantly impact particle diffusion and crossing dynamics, especially when correlations are present.

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Area of Science:

Physics
Physical Chemistry
Statistical Mechanics

Background:

Thermally activated diffusion is fundamental to many physical and chemical processes.
Understanding barrier crossing dynamics is crucial in fields like reaction kinetics and materials science.
Fluctuating barriers introduce complexities not present in static systems.

Purpose of the Study:

To investigate the effects of a fluctuating barrier on the diffusion of particles in underdamped dynamics.
To analyze the role of barrier fluctuation correlations in thermally activated diffusion.
To provide exact solutions for the moments of the diffusion process.

Main Methods:

Application of a Langevin model with additive and multiplicative noises.
Characterization of barrier fluctuations using Gaussian colored noise with exponential correlation.
Derivation of exact solutions for the first and second moments.
Direct numerical simulations to determine asymptotic probabilities.

Main Results:

Exact analytical solutions for the first and second moments of the diffusion process were obtained.
Direct simulations confirmed the theoretical predictions for barrier crossing probability.
The correlation properties of the fluctuating barrier were found to be critically important.
Underdamped dynamics significantly influence the diffusion process over fluctuating barriers.

Conclusions:

The correlation of barrier fluctuations is a key factor governing the dynamics of particle diffusion.
The Langevin model provides a robust framework for studying complex diffusion phenomena.
This research offers insights into systems with dynamic energy landscapes.