Coupled Brownian motors: The entropic mechanism

Recent work have shown the possibility of obtaining, through a noise induced symmetry breaking leading to a nonequilibrium phase transition, a set of coupled Brownian motors. It was also shown that such a system could show negative mobility and anomalous (clockwise) hysteretic behavior. Using a mean-field approximation and a colored multiplicative noise, it was found a contraction of the ordered phase (and re-entrance as a function of the coupling) on one hand, and a shift from anomalous to normal hysteretic behavior on the other. These behavior were obtained when the noise induced phase transition originates from a short time instability. We here discuss a similar system where the noise induced phase transition originates in an entropic mechanism. Preliminary studies indicate the possibility of obtaining non standard hysteretic cycles, with a staircase-like structure. Depending on the parameter region, the hysteresis diagram could have one or more blocks, that can be explored as a whole or step by step, opening the possibility of exploiting it as a noise-controlled multipurpose logic gate.