Abstract Self-assembled In x Ga 1−x As quantum dots (QDs) are promising hosts for spin qubits with excellent coupling to photons. Nuclear spin and charge fluctuations lead to dephasing and limit the applicability of QDs as qubits. We show that charge noise can be minimized by high quality MBE growth of well-designed heterostructures yielding natural optical linewidths down to 1.15 µeV. To minimize the nuclear spin noise, one direction would be to reduce the wave function overlap with the nuclei. We show that this is indeed the case for a single hole spin in a QD that we embedded in the intrinsic region of an n-i-p-diode. For random nuclei, the heavy-hole limit is achieved down to neV energies, equivalent to dephasing times of microseconds.

中文翻译：

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自组装量子点中的超低电荷和自旋噪声

摘要 自组装 In x Ga 1-x As 量子点 (QD) 是自旋量子位的有前途的宿主，与光子具有出色的耦合。核自旋和电荷波动会导致移相并限制 QD 作为量子位的适用性。我们表明，可以通过精心设计的异质结构的高质量 MBE 生长来最小化电荷噪声，从而产生低至 1.15 µeV 的自然光线宽。为了最小化核自旋噪声，一个方向是减少波函数与核的重叠。我们表明，对于嵌入在 nip-diode 的本征区域中的 QD 中的单孔自旋来说，情况确实如此。对于随机核，重空穴限制可达到 neV 能量，相当于微秒的移相时间。