Figure 1

(Color online) Transmission function for a ring with $N=20$ sites, $l_1=9$, $l_2=12$ barriers of height $E_b=1$, $V_1=V_2=0.5$, $w_0=1$, and $\delta =\pi ∕2$. Solid red (dark gray) and dashed black lines correspond, respectively, to $w^{\prime }=0.1,0$. Thick and thin lines correspond to ${\Omega }_0=0.05$ and 0.3, respectively. A scheme of the setup is also included.Reuse & Permissions

Figure 2

(Color online) dc current $J$ as a function of the phase lag for $V_2=1.5V_2$ and $w_0^2=0.5$. Thin black and thick red (dark gray) lines correspond to $V_1=0.2$ and 0.5, respectively. Solid, dashed, and dot-dashed lines correspond to ${\Omega }_0=0.05$, 0.1, and 0.6. Circles correspond to fits with the function $J=A_0+A_1\sin \left(\delta \right)$. The chemical potential is $\mu =0.1$ and $w^{\prime }=1$. Other parameters are as in Fig. 1.Reuse & Permissions

Figure 3

(Color online) dc current $J$ as a function of the coupling to the reservoirs. Upper panel corresponds to $V_1=1.5V_2$ and $\delta =0$ and lower panel corresponds to $V_1=V_2$, with $V_1=0.5$ and $\delta =\pi ∕2$. Circles, squares, diamonds, and up and down triangles correspond to ${\Omega }_0=0.01$, 0.05, 0.45, 0.6, and 0.75, respectively. Other parameters are as in Fig. 2.Reuse & Permissions

Figure 4

(Color online) dc current $J$ as a function of the pumping frequency ${\Omega }_0$ for $\delta =\pi ∕2$. Thin and thick lines correspond to couplings to the reservoirs $w_0^2=0.5$ and 1, respectively. Blue (black) solid and red (dark gray) dashed lines correspond to $\mu =-1.14$ and $V_1=V_2=0.2$ and 0.5, respectively. Black dash-dotted lines correspond to $\mu =-1.14$ and $V_2=1.5V_1$ with $V_1=0.5$. Magenta (gray) two-dot-dashed line corresponds to $V_1=V_2=0.2$ and $\mu =0.1$. Other parameters are as in Fig. 2. The inset shows a zoom for small ${\Omega }_0$.Reuse & Permissions