title: Fractional Fokker-Planck subdiffusion in alternating force fields.
abstract: The fractional Fokker-Planck equation for subdiffusion in time-dependent force fields is derived from the underlying continuous time random walk. Its limitations are discussed and it is then applied to the study of subdiffusion under the influence of a time-periodic rectangular force. As a main result, we show that such a force does not affect the universal scaling relation between the anomalous current and diffusion when applied to the biased dynamics: in the long-time limit, subdiffusion current and anomalous diffusion are immune to the driving. This is in sharp contrast with the unbiased case when the subdiffusion coefficient can be strongly enhanced, i.e., a zero-frequency response to a periodic driving is present.
authors.affiliation: National Institute of Chemical Physics and Biophysics, Rävala 10, Tallinn 15042, Estonia.
authors.forename: E
authors.initials: E
authors.lastname: Heinsalu
authors.forename: M
authors.initials: M
authors.lastname: Patriarca
authors.forename: I
authors.initials: I
authors.lastname: Goychuk
authors.forename: P
authors.initials: P
authors.lastname: Hänggi