title: Random walk with chaotically driven bias.
abstract: We investigate two types of random walks with a fluctuating probability (bias) in which the random walker jumps to the right. One is a 'time-quenched framework' using bias time series such as periodic, quasi-periodic, and chaotic time series (chaotically driven bias). The other is a 'time-annealed framework' using the fluctuating bias generated by a stochastic process, which is not quenched in time. We show that the diffusive properties in the time-quenched framework can be characterised by the ensemble average of the time-averaged variance (ETVAR), whereas the ensemble average of the time-averaged mean square displacement (ETMSD) fails to capture the diffusion, even when the total bias is zero. We demonstrate that the ETVAR increases linearly with time, and the diffusion coefficient can be estimated by the time average of the local diffusion coefficient. In the time-annealed framework, we analytically and numerically show normal diffusion and superdiffusion, similar to the Lévy walk. Our findings will lead to new developments in information and communication technologies, such as efficient energy transfer for information propagation and quick solution searching.
authors.affiliation: WPI Center for MANA, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Song-Ju
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: NSRI, National Institute of Information and Communications Technology, Tokyo 184-8795, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Naruse
authors.affiliation: Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550 &PRESTO JST, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Aono
authors.affiliation: Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi 400-8511, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Hori
authors.affiliation: Department of Mechanical Engineering, Keio University, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Akimoto