Directed transport driven by L\'{e}vy flights coexisting with subdiffusion

TL;DR

This study explores how Brownian particles exhibit directed transport in asymmetric potentials driven by Le9vy flights and subdiffusion, revealing optimal conditions and thresholds for maximal transport efficiency.

Contribution

It introduces a model combining Le9vy flights with subdiffusion in asymmetric potentials, analyzing transport properties without external forces, and identifies key parameters affecting directed motion.

Findings

Group velocity increases with subdiffusive index.

Existence of an optimal Le9vy index for maximum velocity.

Threshold subdiffusive index below which ratchet effects vanish.

Abstract

Transport of the Brownian particles driven by L\'evy flights coexisting with subdiffusion in asymmetric periodic potentials is investigated in the absence of any external driving forces. Using the Langevin-type dynamics with subordination techniques, we obtain the group velocity which can measure the transport. It is found that the group velocity increases monotonically with the subdiffusive index and there exists an optimal value of the L\'evy index at which the group velocity takes its maximal value. There is a threshold value of the subdiffusive index below which the ratchet effects will disappear. The nonthermal character of the L\'evy flights and the asymmetry of the potential are necessary to obtain the directed transport. Some peculiar phenomena induced by the competition between L\'evy flights and subdiffusion are also observed. The pseudonormal diffusion will appear on the level of the median.