Absolute Negative Mobility in a Ratchet Flow

Abstract

This paper is motivated by the transport of suspended particles pumped periodically through a modulated channel filled of water. The resulting flow behaves as a ratchet potential, called ratchet flow, i.e. the particle may drift to a preferential direction without bias. We study the deterministic particle dynamics using continuation of periodic orbits and of periodic transport solutions. The transport exists regardless the parity symmetry of the problem and the bifurcation scenario involve chaotic transitions. Moreover, the influence of the noise is discussed and points out a counter-intuitive consequence. The noise triggers a particle transport in the opposite direction to the bias (Absolute Negative Mobility). We show that this phenomenon is generic for slightly biased ratchet flow problem.