Velocity and diffusion constant of a periodic one-dimensional hopping model

The velocity and the diffusion constant are obtained for a periodic onedimensional hopping model of arbitrary periodN. These two quantities are expressed as explicit functions of all the hopping rates. The velocity and the diffusion constant of random systems are calculated by taking the limit N→Β. One finds by varying the distribution of hopping rates that the diffusion constant and the velocity are singular at different points. Lastly, several possible applications are proposed.