The key to realizing fault-tolerant quantum computation for singlet-triplet (ST) qubits in semiconductor double quantum dot (DQD) is to operate both the single- and two-qubit gates with high fidelity. The feasible way includes operating the qubit near the transverse sweet spot (TSS) to reduce the leading order of the noise, as well as adopting the proper pulse sequences which are immune to noise. The single-qubit gates can be achieved by introducing an AC drive on the detuning near the TSS. The large dipole moment of the DQDs at the TSS has enabled strong coupling between the qubits and the cavity resonator, which leads to two-qubit entangling gates. When operating in the proper region and applying modest pulse sequences, both single- and two-qubit gates have fidelity higher than 99%. The results in this paper suggest that taking advantage of the appropriate pulse sequences near the TSS can be effective to obtain high-fidelity ST qubits.

中文翻译：

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在横向甜蜜点附近实施的通用单线态-三线态量子位

实现半导体双量子点 (DQD) 中单三重态 (ST) 量子位容错量子计算的关键是高保真地操作单量子位门和双量子位门。可行的方法包括在横向甜蜜点（TSS）附近操作量子位以降低噪声的前导阶，以及采用不受噪声影响的适当脉冲序列。单量子位门可以通过在 TSS 附近的失谐上引入交流驱动器来实现。TSS 上 DQD 的大偶极矩使量子位和腔谐振器之间产生强耦合，从而导致两个量子位纠缠门。当在适当的区域运行并应用适度的脉冲序列时，单量子位门和双量子位门的保真度都高于 99%。