Single Electron Spin Qubits in Silicon Quantum Dots
Single Electron Spin Qubits in Silicon Quantum Dots
复制标题
硅量子点中的单电子自旋量子位
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. M. Zajac
中科院分区：
文献类型：
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作者：
D. M. Zajac
量子点中的电子自旋形成了理想的两能级系统，用于实现固态量子计算。虽然自旋态可以具有极长的量子相干时间，但解决单自旋和耦合大自旋阵列一直是艰巨的实验挑战。过去几十年的研究已经产生了各种创造性的方法来解决这些问题，对半导体中的自旋物理学产生了新的见解，并证明了量子计算的许多基本标准。本文对少电子Si/SiGe量子点中自旋的物理和量子控制进行了系统的研究。我们提出了新的量子点器件设计，提高了对单电子波函数的控制。我们通过将量子点放置在由微米级铁磁体产生的强磁场梯度附近，展示了对单电子自旋态的完全控制，并使用随机基准测试量化了控制保真度。利用相邻自旋与任意单自旋之间的交换相互作用，我们提出了在单个设备中具有电子自旋的通用量子计算（初始化，读出和通用门集）的所有标准的第一个演示之一。最后，我们迈出了第一步，通过确定性地穿梭单个电子通过9个量子点阵列来控制大型量子点阵列。
Electron spins in quantum dots form ideal two-level systems for implementing quantum computation in the solid state. While spin states can have extremely long quantum coherence times, addressing single spins and coupling large arrays of spins have been formidable experimental challenges. Research over the past several decades has resulted in a variety of creative approaches to address these problems, yielded new insights into the physics of spins in semiconductors, and demonstrated many of the basic criteria for quantum computation. This thesis presents a systematic study of the physics and quantum control of spins in few-electron Si/SiGe quantum dots. We present novel designs for quantum dot devices that yield improved control of single electron wavefunctions. We demonstrate full control of single electron spin states by placing a quantum dot in the vicinity of a strong magnetic field gradient produced by a micron-scale ferromagnet, and quantify the control fidelity using randomized benchmarking. Utilizing the exchange interaction between neighboring spins in combination with arbitrary single-spin rotations, we present one of the first demonstrations of all the criteria for universal quantum computation (initialization, readout, and a universal set of gates) with electron spins in a single device. Finally, we take the first steps towards controlling a large array of quantum dots by deterministically shuttling single electrons through an array of nine quantum dots.