Abstract:
The high-temperature unidirectional motion of a Brownian particle with time-dependent potential energy described by a spatially asymmetric periodic function is considered. A general formula derived for the mean velocity ν of such a motion is specified for dichotomic deterministic and Markovian stochastic processes. In both cases, ν increases linearly for low-frequencies γ of potential-energy fluctuations and reaches maxima for γ about the inverse time of diffusion by the spatial period of the potential. The behaviors of ν for large γ values are different in these cases: ν ∝ γ−2 and ν ts γ−1 for the deterministic and stochastic processes, respectively. It is shown that the direction of the motor motion depends on the relative lifetimes of each of the dichotomic-process states if the amplitude of the potential-energy fluctuations is fairly large in comparison with the mean value.
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