Fluctuation-driven directed transport in the presence of Levy flights
- ORNL
- Institute for Theoretical Physics NSC KIPT, Kharkov, Ukraine
The role of Levy flights on fluctuation-driven transport in time independent periodic potentials with broken spatial symmetry is studied. Two complementary approaches are followed. The first one is based on a generalized Langevin model describing overdamped dynamics in a ratchet type external potential driven by Levy white noise with stability index {alpha} in the range 1 < {alpha} < 2. The second approach is based on the space fractional Fokker-Planck equation describing the corresponding probability density function (PDF) of particle displacements. It is observed that, even in the absence of an external tilting force or a bias in the noise, the Levy flights drive the system out of the thermodynamic equilibrium and generate an up-hill current (i.e., a current in the direction of the steeper side of the asymmetric potential). For small values of the noise intensity there is an optimal value of {alpha} yielding the maximum current. The direction and magnitude of the current can be manipulated by changing the Levy noise asymmetry and the potential asymmetry. For a sharply localized initial condition, the PDF of staying at the minimum of the potential exhibits scaling behavior in time with an exponent bigger than the -1/{alpha} exponent corresponding to the force free case.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1001271
- Journal Information:
- Physica A: Statistical Mechanics and its Applications, Vol. 387, Issue 27; ISSN 0378-4371
- Country of Publication:
- United States
- Language:
- English
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