Quadrupolar Exchange-Only Spin Qubit.
Quadrupolar Exchange-Only Spin Qubit.
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DOI：
10.1103/physrevlett.121.177701
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发表时间：
2018-07
影响因子：
8.6
通讯作者：
M. Russ;J. Petta;G. Burkard
中科院分区：
文献类型：
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作者：
M. Russ;J. Petta;G. Burkard
我们提出了一种四极交换自旋量子比特，它对量子点中占主导地位的退相干机制电荷噪声和核自旋退相具有高度鲁棒性。量子比特由被捕获在三个量子点中的四个电子组成，并在无退相干子空间中运行，以减轻由于核自旋引起的退相。为了降低对电荷噪声的敏感性，量子位可以完全在扩展的电荷噪声最佳点处操作，该最佳点对电波动一阶不敏感。由于库仑相互作用介导的现场交换，量子比特能量分裂是电可控的，即使在“关闭”配置中也可以达到几GHz，使其与传统的微波腔兼容。
We propose a quadrupolar exchange-only spin qubit that is highly robust against charge noise and nuclear spin dephasing, the dominant decoherence mechanisms in quantum dots. The qubit consists of four electrons trapped in three quantum dots, and operates in a decoherence-free subspace to mitigate dephasing due to nuclear spins. To reduce sensitivity to charge noise, the qubit can be completely operated at an extended charge noise sweet spot that is first-order insensitive to electrical fluctuations. Because of on-site exchange mediated by the Coulomb interaction, the qubit energy splitting is electrically controllable and can amount to several GHz even in the "off" configuration, making it compatible with conventional microwave cavities.