半导体自旋量子比特的无储层、无测量微波初始化
Reservoir- and Measurement-free Microwave Initialization of Semiconductor Spin Qubits
浏览论文内容
中文总结 AI 辅助
本文展示了一种无储层、无测量的固定微波脉冲序列初始化硅自旋量子比特对的方法，通过单重态-三重态物理实现高保真初始化，为可扩展量子处理器提供了新方案。
中文摘要 AI 辅助
可扩展量子处理器需要在整个大型阵列中重复进行量子比特初始化。在半导体自旋量子比特中，快速初始化通常依赖于局部储层访问或基于测量的反馈，这需要专门的基础设施，随着处理器规模的扩大，这些基础设施越来越难以分布。在此，我们展示了一种在工业制造的Si/SiGe量子点器件中，使用固定的微波和基带脉冲序列，对硅自旋量子比特对进行无储层、无测量初始化。奇数自旋宇称态弛豫到单重态电荷态，而受阻的偶数自旋宇称态则通过三重态流形进行微波驱动，随后通过单重态-三重态混合和电荷杂化转换为单重态。重复循环产生与单重态相关的电荷结果，在采样的制备态中，中位概率为99.4%，而交换谱学独立验证了到目标$|\uparrow\downarrow\rangle$操作态的映射。微波谱学和时域测量识别了暗态限制的单周期转移以及随后设置初始化时间尺度的阻塞解除动力学。所展示的泵浦序列使用大约$12\\,\mu\mathrm{s}$的微波脉冲和混合停留时间，而我们预计在改进的器件条件下可实现亚微秒初始化。这些结果确立了固定序列微波初始化作为半导体自旋量子比特处理器的可扩展控制原语，基于单重态-三重态物理，可适用于具有合适泡利阻塞跃迁的平台。
英文摘要
Scalable quantum processors require repeated qubit initialization throughout large arrays. In semiconductor spin qubits, fast initialization commonly relies on local reservoir access or measurement-based feedback, requiring dedicated infrastructure that becomes increasingly difficult to distribute as processors scale. Here, we demonstrate reservoir- and measurement-free initialization of a silicon spin-qubit pair in an industrially fabricated Si/SiGe quantum-dot device using a fixed sequence of microwave and baseband pulses. Odd spin-parity states relax to the singlet charge state, whereas blocked even spin-parity states are microwave-driven through the triplet manifold and subsequently converted to the singlet by singlet-triplet mixing and charge hybridization. Repeated cycles produce the singlet-associated charge outcome with a median probability of 99.4% across the sampled preparation states, while exchange spectroscopy independently verifies mapping to the target $|\uparrow\downarrow\rangle$ operational state. Microwave spectroscopy and time-domain measurements identify the dark-state-limited single-cycle transfer and the subsequent blockade-lifting dynamics that set the initialization time scale. The demonstrated pumping sequence uses approximately $12\,μ\mathrm{s}$ of microwave bursts and mixing dwells, while we project sub-microsecond initialization under improved device conditions. These results establish fixed-sequence microwave initialization as a scalable control primitive for semiconductor spin-qubit processors, based on singlet-triplet physics that can be adapted to platforms with suitable Pauli-blockade transitions.
发表机构
- RIKEN（理化学研究所）
机构由 AI 辅助整理，请以论文原文为准。
