Effective diffusion coefficient in tilted disordered potentials: Optimal relative diffusivity at a finite temperature

Abstract

In this work we study the transport properties of non-interacting overdamped particles, moving on tilted disordered potentials, subjected to Gaussian white noise. We give exact formulas for the drift and diffusion coefficients for the case of random potentials resulting from the interaction of a particle with a "random polymer". In our model the "random polymer" is made up, by means of some stochastic process, of monomers that can be taken from a finite or countable infinite set of possible monomer types. For the case of uncorrelated random polymers we found that the diffusion coefficient exhibits a non-monotonous behavior as a function of the noise intensity. Particularly interesting is the fact that the relative diffusivity becomes optimal at a finite temperature, a behavior which is reminiscent to that of stochastic resonance. We explain this effect as an interplay between the deterministic and noisy dynamics of the system. We also show that this behavior of the diffusion coefficient at a finite temperature is more pronounced for the case of weakly disordered potentials. We test our findings by means of numerical simulations of the corresponding Langevin dynamics of an ensemble of noninteracting overdamped particles diffusing on uncorrelated random potentials.

15 pages, 7 figures

References in corpus (6)

• Artificial Brownian motors: Controlling transport on the nanoscale
• The long reach of DNA sequence heterogeneity in diffusive processes
• Weak disorder strongly improves the selective enhancement of diffusion in a tilted periodic potential
• Arrival time distribution for a driven system containing quenched dichotomous disorder
• Biased diffusion in a piecewise linear random potential
• Driven classical diffusion with strong correlated disorder