Efficiency of interacting Brownian motors

Frantisek Slanina

Institute of Physics, Czech Academy of Sciences, Na Slovance 2, CZ-18221 Prague, Czech Republic

Rectification of thermal fluctuations into steady current is achieved in Brownian motors by the ratchet effect. Generically, requirements of maximum current and maximum energetical efficiency are never achieved simultaneously. Here, we formulate a model of strongly interacting particles in a rocking ratchet and study it using numerical simulations. We investigate the dependence of current and efficiency on temperature, particle density and interaction strength. While weak interactions typically decrease both current and efficiency, for strong enough interactions we find a region of parameters where the efficiency is enhanced by the interaction. As for the current, we observe smooth crossover from standard non-interacting particle behaviour to the behaviour well known for asymmetric exclusion process (ASEP) or traffic models. The work can have applications both for tuning parameters of practically realized brownian motors and as a suggestion for simple physical implementation of the ASEP model, considered usually rather as an abstraction.