Brownian Motion Exhibiting Absolute Negative Mobility

We consider a single Brownian particle in a spatially symmetric, periodic system far from thermal equilibrium. This setup can be readily realized experimentally. Upon application of an external static force $F$, the average particle velocity is negative for $F>\mathrm{}0\mathrm{}$ and positive for $F<\mathrm{}0\mathrm{}$ (absolute negative mobility).