Applications of Brownian motors

Abstract

Brownian motors combine asymmetry (such as a ratchet potential) and stochastic (thermal) motion with nonequilibrium processes to generate directed particle flow. A brief general introduction to Brownian motors is given, and the relevance of the ratchet model for biological motor proteins is highlighted. However, the impact of research on Brownian motors goes far beyond biophysics. A wealth of novel phenomena has been predicted, and some of these phenomena have been observed in areas as diverse as synthetic chemistry, bio-molecular colloids, selforganizing systems, quantum electronics, micro-fluidics, and materials science. Applications, such as novel actuators and molecular separation techniques, are evolving quickly. In the oral presentation, I will attempt to give an overview on applications of ratchets and Brownian motors. In the present paper, I give a short overview and review then a recent experimental realization of a tunneling ratchet for electrons. Such electron tunnelling ratchets can not only be used to generate particle currents, but also to pump heat. Using a realistic model, the heat pumping properties of the experimental electron ratchet are analysed.