A biologically inspired ratchet model of two coupled Brownian motors

A ratchet model for coupled Brownian motors, inspired by the motion of individual two-headed molecular motors on cytoskeletal filaments, is proposed. Such motors are modeled as two elastically coupled Brownian particles, each of which moves in a flashing ratchet potential. The ratchet potentials felt by the individual particles are anti-correlated, modeling the successive binding and unbinding of the two motor heads to the filament. We obtain, via Langevin simulations, steady-state currents as functions of noise strength, the equilibrium separation of the particles and the rate of switching between potential states. We observe an enhanced current due to coupling, noise-induced stability and phase-locked behaviour in the deterministic regime. A qualitative understanding of these features is provided.