Analytical model of a brownian motor with a fluctuating potential

2019-09-25 23:25:16

motor model energy potential Brownian

责任者: Rozenbaum, V.M.;Korochkova, T.E. 单位: Institute of Surface Chemistry, Natl. Academy of Sciences of Ukraine, Kiev, 03164, Ukraine 来源出处: Journal of Experimental and Theoretical Physics,2005,100(1):218-227 摘要: We propose a model of a Brownian motor that performs a useful work against a load force F in an asymmetric periodic potential V(x) = V(x + 2L) that undergoes random shifts by a half period L with a frequency γ. An arbitrarily shaped potential profile is repeated with an energy shift ΔV in both half-periods L, while the periodicity of the function V(x) is ensured by its jumps at x = 0 and x = L. The boundary condition at x = 0 for the distribution function of a Brownian particle allows us to introduce a high and narrow potential barrier V0 that blocks the reverse current and leads to high efficiency of the motor (the ratio of the useful work done against the load force F to the energy imparted to the particle through the potential shifts). Based on this model, we derived exact analytical expressions for the current J and the efficiency η. In the special case of piecewise-linear potentials, J and η were plotted against F and γ for various values of the parameters ΔV and V0. We discuss the influence of the potential shape and fluctuation frequency on the main characteristics of the motor. © 2005 Pleiades Publishing, Inc. 关键词: Brownian movement;Motors;Electric potential;Mathematical models;Nanostructured materials;Electric fields;Electric currents;Molecular physics;Difference equations;Piecewise linear techniques;Molecular pumps;Mechanical energy;Nanomachines;Brownian particles