May 2007
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12 Reads
The hopping motion of particles on segments of linear chains is considered, where the transition rates correspond to nonsymmetric potentials. Attention is drawn to the directional dependence of the particle current, for various strengths of the applied bias field. The problem is mainly discussed in connection with the mean first-passage time of particles across the segment. Directional effects are absent in the regime of linear response; they appear for strong bias fields and nonsymmetric potentials which comprise different barriers and site energies. The results are compared with numerical simulations and an exact expression.