Figure 8.

The diffusion coefficient D plotted against the number of sites N per cycle by keeping the entropy production per cycle $\sigma$ and velocity v constant. The chosen time interval $\Delta t$ for given N is restricted by the inequality (46). We take $\Delta t(a,N)=a\frac{\Delta x}{v}tanh\left[\frac{\sigma }{2N{k}_B}\right]$ (where $0\le a\le 1$) and depict $D(a,N)$ with $a=0$ (blue curve), $a=0.6$ (black curve), and $a=1$ (green curve). We chose the produced entropy per cycle to be $\sigma /k_B=10$ for $N\ge 3$.