Paradoxical directed diffusion due to temperature anisotropies

An analytically tractable, but still experimentally realistic model dynamics is investigated, describing the Brownian motion of a particle in a "meandering" periodic potential landscape under the simultaneous influence of two different heat baths. The main characteristics of the resulting far-from-equilibrium environment is an anisotropy of the ambient temperature. When an external static force F is applied, the particle moves in the direction opposite to that force (absolute negative mobility), and this even for arbitrarily large forces \F\. Moreover, even when the "meandering" potential exhibits a, broken spatial symmetry, no preferential direction of motion arises for F = 0.