论文标题
驱动的Andreev分子
Driven Andreev molecule
论文作者
论文摘要
我们研究了三个末端S-QD-S-QD-S约瑟夫森连接，偏向于相应电压。在没有施加电压的情况下，每个量子点上的Andreev结合态杂交形成了“ Andreev分子”。但是，缺乏在非平衡设置中对该系统的理解。在生物结上施加直流电压会使系统时间周期性，而平衡的Andreev结合状态随着多个Andreev反射（MAR）而导致有限的寿命的共振梯子演变为一个共振阶梯。从时间周期性的bogoliubov-de Gennes方程开始，我们将问题映射到（无限）浮标空间中的紧密结合链。该非铁块基质的分解是通过持续分数方法获得的。我们从数值上计算了Floquet Andreev光谱，该光谱可以通过点上的局部隧道光谱探测。我们还考虑了子仪电流，并表明Floquet共振决定了MAR步骤的位置。两个点的接近性会导致步骤分裂，而在大距离处，我们观察到干扰效应，从而导致I-V曲线中的振荡。后一种效果应长时间持续。
We study the three terminal S-QD-S-QD-S Josephson junction biased with commensurate voltages. In the absence of an applied voltage, the Andreev bound states on each quantum dot hybridize forming an `Andreev molecule'. However, understanding of this system in a non-equilibrium setup is lacking. Applying a dc voltage on the bijunction makes the system time-periodic, and the equilibrium Andreev bound states evolve into a ladder of resonances with a finite lifetime due to multiple Andreev reflections (MAR). Starting from the time-periodic Bogoliubov-de Gennes equations we map the problem to a tight-binding chain in the (infinite) Floquet space. The resolvent of this non-Hermitian block matrix is obtained via a continued fraction method. We numerically calculate the Floquet-Andreev spectra which could be probed by local tunneling spectroscopy on the dots. We also consider the subgap current, and show that the Floquet resonances determine the position of the MAR steps. Proximity of the two dots causes splitting of the steps, while at large distances we observe interference effects which cause oscillations in the I-V curves. The latter effect should persist at very long distances.
