Coupled Brownian motors

A set of coupled Brownian motors -- resulting from a noise-induced phase transition generated through an entropic mechanism, and formerly studied in mean-field approximation -- is numerically integrated by Heun’s method. The results add much insight to the mean-field ones, allowing interpretation of the underlying mechanisms. It turns out that the low-noise boundary of the ordered phase obtained in mean-field approximation lies near a region where the order parameter is negative. Hints of bistability and negative mobility around F = 0 are seen in two cases, and anomalous hysteresis is confirmed in one case.