Disordering effects of colour in a system of coupled Brownian motors: phase diagram and anomalous-to-normal hysteresis transition

A system of periodically coupled nonlinear phase oscillators—submitted to both additive and multiplicative white noises—has been recently shown to exhibit ratchetlike transport, negative zero-bias conductance, and anomalous hysteresis. These features stem from the asymmetry of the stationary probability distribution function, arising through a noise-induced nonequilibrium phase transition which is reentrant as a function of the multiplicative noise intensity. Using an explicit mean-field approximation we analyze the effect of the multiplicative noises being coloured, finding a contraction of the ordered phase (and a reentrance as a function of the coupling) on one hand, and a shift of the transition from anomalous to normal hysteresis inside this phase on the other. Member of CONICET, Argentina; E-mail: [email protected] http://www.cab.cnea.gov.ar/CAB/invbasica/FisEstad/estadis.htm