硅双量子点中隧穿和谷耦合参数的完整测量
Complete measurement of tunnel- and valley-coupling parameters in a silicon double quantum dot
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中文总结 AI 辅助
研究硅双量子点中隧穿和谷耦合参数，通过全面表征谷内和谷间隧道耦合及其复相位，揭示其对可测量参数的控制作用，完善了对谷耦合全样本变化及相关物理参数的理解。
中文摘要 AI 辅助
隧穿在量子点量子比特的初始化、测量和控制中至关重要。在硅中，这种隧穿不仅连接量子比特状态，还连接布里渊区两侧导带中的谷最小值，对量子点行为有重大影响。本文全面表征了谷内和谷间隧道耦合，包括其复相位——谷相位。这些相位控制可测量参数，如双量子点量子态反交叉处的能隙比。谷相位随量子点栅极电压变化，取决于量子阱的底层原子结构。了解谷相位完善了图景，填补了我们对谷耦合全样本变化以及依赖于它们的物理参数理解上的关键空白，包括自旋轨道耦合、谷轨道混合和朗德g因子。
英文摘要
Tunneling is essential in the initialization, measurement, and control of quantum dot qubits. In silicon, such tunneling connects not only the qubit states but also valley minima in the conduction band on opposite sides of the Brillouin zone, with large consequences for the quantum dot behavior. Here we present a full characterization of the intravalley and intervalley tunnel couplings, including their complex phases -- the valley phases. These phases are shown to control measurable parameters, including the ratios of the gaps at anticrossings between quantum states of a double quantum dot. The valley phases themselves evolve as a function of the quantum dot gate voltages and depend on the underlying atomic structure of the quantum well. Knowledge of the valley phases completes the picture and fills a key gap in our understanding of sample-wide variations of valley couplings and the physical parameters that depend on them, including spin-orbit coupling, valley-orbit mixing, and Landé $g$-factors.
