Liu Chun-Xiao, Wang Guanzhong, Dvir Tom, Wimmer Michael
Qutech and Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, Netherlands.
Phys Rev Lett. 2022 Dec 23;129(26):267701. doi: 10.1103/PhysRevLett.129.267701.
Semiconductor quantum dots have proven to be a useful platform for quantum simulation in the solid state. However, implementing a superconducting coupling between quantum dots mediated by a Cooper pair has so far suffered from limited tunability and strong suppression. This has limited applications such as Cooper pair splitting and quantum dot simulation of topological Kitaev chains. In this Letter, we propose how to mediate tunable effective couplings via Andreev bound states in a semiconductor-superconductor nanowire connecting two quantum dots. We show that in this way it is possible to individually control both the coupling mediated by Cooper pairs and by single electrons by changing the properties of the Andreev bound states with easily accessible experimental parameters. In addition, the problem of coupling suppression is greatly mitigated. We also propose how to experimentally extract the coupling strengths from resonant current in a three-terminal junction. Our proposal will enable future experiments that have not been possible so far.
半导体量子点已被证明是固态量子模拟的一个有用平台。然而，迄今为止，实现由库珀对介导的量子点之间的超导耦合一直受到可调谐性有限和强抑制的困扰。这限制了诸如库珀对分裂和拓扑基塔耶夫链的量子点模拟等应用。在本信函中，我们提出如何通过连接两个量子点的半导体 - 超导体纳米线中的安德列夫束缚态来介导可调谐的有效耦合。我们表明，通过这种方式，可以通过用易于获取的实验参数改变安德列夫束缚态的性质，分别控制由库珀对和单电子介导的耦合。此外，耦合抑制问题也大大减轻。我们还提出了如何从三端结中的共振电流实验提取耦合强度。我们的提议将使迄今为止无法进行的未来实验成为可能。
