Correlation between diffusion and coherence in Brownian motion on a tilted periodic potential
نویسندگان
چکیده
The paper studies the overdamped motion of Brownian particles in a tilted saw-tooth potential. The dependencies of the diffusion coefficient and coherence level of Brownian transport on temperature, tilting force, and the shape of the potential are analyzed. It is demonstrated that at low temperatures the coherence level of Brow-nian transport stabilizes in the extensive domain of the tilting force where the value of the Péclet factor is P e = 2. This domain coincides with the one where the enhancement of the diffusion coefficient versus the tilting force is the most rapid. The necessary and sufficient conditions for the non-monotonic behaviour of the diffusion coefficient as a function of temperature are found. The effect of the acceleration of diffusion by bias and temperature is demonstrated to be very sensitive to the value of the asymmetry parameter of the potential. In recent years the anomalous properties of thermal diffusion in tilted periodic potentials have been considered in a number of papers [1,2,3,4,5]. The effect of the giant amplification of diffusion by bias with respect to free diffusion was observed [2,3] and the non-monotonic behaviour of the diffusion coefficient as a function of temperature was found [4]. The influence of spatially modulated friction on diffusion and coherent transport in a tilted washboard potential was investigated in Ref. [5], and similar effects caused by spatially periodic temperature were discussed in Ref. [6].
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