Towards a Logical Qubit in Silicon: Scalable 2-qubits Operations in CMOS-compatible Quantum Dots

量子计算有望解决各种领域的棘手问题，如药物设计、材料科学或数据预测。目前正在研究几种硬件平台来托管量子计算机，目前尚不清楚哪种方案将是计算的最佳方案。硅量子点中的自旋量子比特由于其巨大的量子比特密度和与硅-cmos产业的兼容性，是很有希望的候选者。然而，实现硅基量子计算机的一些关键构件仍有待证明。特别是，在二维阵列中实现量子点量子比特的相干控制还有待展示。这需要仔细考虑诸如传感器、一个量子比特门和两个量子比特门元件等架构元素，以确保一致性以及选择性控制。对于这个PHD，我们希望构建第一个硅自旋量子位阵列，在工业铸造制造的器件中，在平面的两个维度上显示相干的两个量子位门。这将是构建硅量子比特纠错单元的关键要素，并将为实现工业可扩展的量子处理器铺平道路。由于定义量子比特的量子点之间的噪声相互作用，当增加量子比特阵列的维度时，这种相互作用得到增强，因此这样的项目具有挑战性。本博士学位将建立在约翰·莫顿教授的研究小组对线性阵列中硅自旋量子比特的传感和控制的专业知识的基础上，目的是实现对二维自旋量子比特阵列中纠缠的相干控制。

Quantum computing holds the promise to solve intractable problems in various domains, such as drug designs, material science or data prediction. Several hardware platforms are being investigated to host quantum computers, and it is still unclear which scheme will be optimal for computation. Spin qubits in silicon quantum dots are promising candidates given their large qubit density and their compatibility with the silicon-CMOS industry. However, some key building blocks toachieve a silicon-based quantum computer are still to be demonstrated. In particular, realising coherent control of quantum-dot qubits in a two-dimensional array remains to be shown. This requires careful thinking of architectural elements such as sensors, one-qubit gate and two-qubit gate elements to guarantee coherence along with selective control. For this PhD, we look to construct the first silicon spin qubits array displaying coherent two-qubit gates in the two dimensions of the plane, in devices fabricated in industrial foundry. This will be an essential ingredient to building an error-corrected unit cell of silicon qubits, and will pave the way to industrially-scalable quantum processors. Such project is challenging due to the noisy interaction between the quantum dots defining the qubits, enhanced when increasing the dimensions of the qubit array. This PhD will build on the expertise of Prof. John Morton's research group on sensing and controllingsilicon spin qubits in linear arrays, with the aim to achieve coherent control of entanglement in 2D spin qubits array.