基于InAs纳米线的可扩展耦合多量子点器件的实验构筑和精密电学调控研究

本项目采用分子束外延技术获得的高品质InAs纳米线，在其上采用先进微纳加工工艺制作顶指栅电极阵列，构筑耦合半导体多量子点的自旋量子比特器件。即在单个InAs纳米线实现多个（4个或4个以上）隧穿耦合在一起的高可控半导体量子点量子比特器件的集成，同时在附近的单根纳米线上实现单量子点，并用连桥栅电极电容耦合到多量子点上，实现量子态的探测和读出。利用超低温和低噪声电学测试系统，结合原位集成的电荷感应器，研究耦合多量子点中的电荷稳态图和自旋输运特性，以及量子点间的自旋交换和超交换相互作用。利用量子点间的近临耦合效应实现近临量子比特间的隧穿耦合、利用高阶共隧穿效应实现远距量子点间的耦合，最终实现量子比特器件中的全部量子点间的可控耦合。通过精密电学测量研究多量子点自旋量子比特间的纠缠状态，探讨自旋的退相干机制和维持纠缠的技术方案。探索利用相干调控技术，完成基本量子模拟实验和建立通用量子逻辑门。

This project aims at realization of integrated qubit devices based on multiple quantum dots (QDs) made from MBE grown high crystalline quality InAs nanowires using state of the art nanofabrication technology and at establishment of a semiconductor based platform for quantum simulation and quantum computation technology. The objectives of the project include: (1) to achieve a quantum chip with four or more than four qubits integrated on a single InAs nanowire by employing local top-finger gate technique; (2) to achieve integration of such a multiple qubit device with a charge sensor made on another single InAs and thus to study the physics of spin transfer, spin superexchange, and spin decoherence in the semiconductor multiple qubit device; (3) to achieve entanglement of every two qubits in an InAs nanowire based multiple qubit device; and (4) to perform quantum simulation experiment and to build quantum logic gates based on the platform of semiconductor QDs made from InAs nanowire.