White-Noise-Induced Transport in Periodic Structures

Spatially periodic structures are exposed to additive Poissonian white shot noise of zero average. Because the underlying master equation no longer obeys the principle of detailed balance, these non-equilibrium fluctuations induce a macroscopic current—even in the absence of spatial asymmetry. The resulting current can be expressed in analytical closed form and we discuss its behaviour in the limits of very weak and very strong noise intensities. We find that the current increases monotonically and—in contrast to common intuition—saturates at infinitely strong noise intensity. The role of internal symmetries of the periodic structure is investigated from the viewpoint of optimizing the current amplitude at fixed noise intensity.