Triple quantum dots (TQDs) are promising semiconductor spin qubits because of their all-electrical control via fast, tunable exchange interactions and immunity to global magnetic fluctuations. These qubits can experience strong transverse interaction with photons in the resonant exchange (RX) regime, when exchange is simultaneously active on both qubit axes. However, most theoretical work has been based on phenomenological Fermi–Hubbard models, which may not fully capture the complexity of the qubit spin-charge states in this regime. Here we investigate exchange in Si/SiGe and GaAs TQDs using full configuration interaction (FCI) calculations which better describe practical device operation. We show that high exchange operation in general, and the RX regime in particular, can differ significantly from simple models, presenting new challenges and opportunities for spin–photon coupling. We highlight the impact of device electrostatics and effective mass on exchange and identify a n...

中文翻译：

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自旋光子转导的三量子点量子位中的共振交换操作

三重量子点（TQD）是有前途的半导体自旋量子位，因为它们通过快速，可调节的交换相互作用进行全电控制，并且不受全局磁波动的影响。当交换同时在两个量子位轴上激活时，这些量子位会在共振交换（RX）机制中与光子发生强烈的横向相互作用。但是，大多数理论工作都是基于现象学的费米－哈伯德模型，在这种情况下可能无法完全捕捉到量子位自旋电荷态的复杂性。在这里，我们使用完全配置交互（FCI）计算来研究Si / SiGe和GaAs TQD中的交换，从而更好地描述了实际的器件操作。我们显示，一般而言，高交换操作（尤其是RX机制）与简单模型有很大的不同，提出了自旋光子耦合的新挑战和机遇。我们强调了设备静电和有效质量对交换的影响，并确定了一种有效的方法。