论文标题
关于多电体量子点系统中磁场调节的交换相互作用的微观理论
Microscopic theory on magnetic-field-tuned sweet spot of exchange interactions in multielectron quantum-dot systems
论文作者
论文摘要
在双Quantum-Dot系统中由两电子状态定义的单线量子Qubit中的交换相互作用（“两电子单曲 - 三个曲线Qubit”）通常会随着交换相互作用而单调而变化，因此没有甜蜜的位置。在这里，我们研究了由双量子点系统中四电子状态定义的单线 - 三个Qubit（“四电子单曲线 - 怪物Qubit”）。我们使用构型交互计算证明，在四电子单曲 - 三个旋转量子Qubit中，交换能量随着失调的函数可能是非单调的，这表明存在甜蜜的斑点。我们进一步表明，垂直磁场对甜点和相应的交换能量的调整可能与轨道分裂的变化有关。我们的结果表明，具有两个以上电子的单线量子标式可以在实现量子计算方面具有优势。
The exchange interaction in a singlet-triplet qubit defined by two-electron states in the double-quantum-dot system ("two-electron singlet-triplet qubit") typically varies monotonically with the exchange interaction and thus carries no sweet spot. Here we study a singlet-triplet qubit defined by four-electron states in the double-quantum-dot system ("four-electron singlet-triplet qubit"). We demonstrate, using configuration-interaction calculations, that in the four-electron singlet-triplet qubit the exchange energy as a function of detuning can be non-monotonic, suggesting existence of sweet spots. We further show that the tuning of the sweet spot and the corresponding exchange energy by perpendicular magnetic field can be related to the variation of orbital splitting. Our results suggest that a singlet-triplet qubit with more than two electrons can have advantages in the realization of quantum computing.
