Ratchet effect of a dimer with broken friction symmetry in a symmetric potential

Abstract

The one-dimensional overdamped Brownian motion of a dimer consisting of two harmonically interacting components is considered. Both components are coupled to the same heat bath and feel the same spatially periodic symmetric potential, whose amplitude is modulated periodically in time. The friction coefficients may differ between dimer components, thus breaking the dynamical symmetry of the system. In the absence of any external bias, a ratchet effect (directed transport) arises generically. Two accurate approximations for the dimer's velocity and diffusion coefficient are obtained for weak and strong couplings. The velocity of the system can be maximized for each direction by adding an optimal amount of noise and by tuning the driving frequency to an optimal value. Furthermore, there exist two optimal coupling strengths at which the velocity is the largest.

Fluctuation-induced transport of two coupled particles: Effect of the interparticle interaction

“…[21][22][23][24][25][26][27] A combined effect of a spatially periodic potential, whose amplitude is time-periodically modulated, and friction asymmetry has been demonstrated in Ref. 28. The rectification mechanism in protein translocation through a pore into a cell may be effected by binding intracellular particles.…”

“…Noiseinduced transport of two coupled particles has been considered in several different ways. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Most of them are based on rectifying Brownian motion by periodic, asymmetric (ratchet) potential in which the dimer moves. [16][17][18] Other approaches, in which the necessary spatial symmetry breaking is provided by an asymmetry inherent to the system itself rather than to its environment, are also available.…”

Double-temperature ratchet model and current reversal of coupled Brownian motors

“…A nonequilibrium environment and broken symmetry of the system are indispensable conditions for directional transport of particles in a ratchet model. Symmetry breaking generally includes the symmetry breaking of the periodic potential field, the symmetry breaking induced by nonequilibrium perturbations, and the breaking induced by mutual coupling between elements of the system [17][18][19][20][21][22][23][24][25][26][27].…”

Inertial frictional ratchets and their load bearing efficiencies

“…Ratchet effect has been obtained in symmetrically periodic overdamped [33][34][35][36] as well as underdamped [11,24,26,[37][38][39] frictionally nonuniform systems. In Ref.…”