Flux of Particles in Sawtooth Media

We study Brownian motion in chains of segments with flashing sawtoothlike potentials. In all former models for stochastic ratchets a coherent switching of the potential is assumed. We consider the generalized case which allows independent switchings of the potential in single segments. We introduce three different rules: correlated, anticorrelated, and uncorrelated switchings. On the basis of a discrete model analytical results for the mean flux are compared with computer simulations. As a result the mean flux will be enhanced for anticorrelated and uncorrelated sawteeth as compared with the case of correlated (coherent) segments.