Figure 3.

Efficiency at steady state $\eta$ plotted against the number of sites N per cycle by keeping the velocity v and diffusion constant D constant. We depict $\eta$ for $v_1=0.5v$, $v_2=0.8v$ and $v_3=v$, where we chose $v=\frac{3D}{\pi R}$ to be within the bounds implied by $\beta \ge 0$ of Equation (13) for $N\ge 3$. We chose the force $f\equiv vT{\dot{\sigma }}_{SS}(N\to \infty )=3k_{B}T/\pi R$. Inset: Damping constant $\gamma \equiv \gamma \left(v\right)D/\left(k_{B}T\right)=TD{\dot{\sigma }}_{SS}/\left(v^2{k}_{B}T\right)$ in dependence of the velocity for different N.