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arXiv 1602.08334cond-mat.mes-hall
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微磁体作用下Si/SiGe量子点中电子自旋的门保真度和相干性

Gate fidelity and coherence of an electron spin in a Si/SiGe quantum dot with micromagnet

E. Kawakami, T. Jullien, P. Scarlino, D. R. Ward, D. E. Savage, M. G. Lagally, V. V. Dobrovitski, Mark Friesen, S. N. Coppersmith, M. A. Eriksson, L. M. K. Vandersypen

摘要:

量子比特的门保真度和相干时间是量子计算的重要基准。我们在Si/SiGe量子点中利用单电子自旋构造量子比特,并通过来自微磁体的人工自旋轨道场对其进行电控制。我们使用随机基准测试测量了$\approx$ 99 $\%$的平均单量子位门保真度,这与衬底中缓慢演变的核自旋的退相一致。对于128个去耦脉冲,使用动态去耦测量的相干时间扩展到$\approx$ 400 $μ$ s,没有饱和的迹象。我们发现的证据表明,在10 kHz的$-$ 1 MHz的范围内的噪声的相干时间是有限的,可能是因为电荷噪声通过微磁梯度影响自旋。这项工作表明,在Si/SiGe量子点的电子自旋是一个很好的候选人,量子信息处理以及量子存储器,即使没有同位素纯化。

英文摘要:

The gate fidelity and the coherence time of a qubit are important benchmarks for quantum computation. We construct a qubit using a single electron spin in a Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of $\approx$ 99$\%$ using randomized benchmarking, which is consistent with dephasing from the slowly evolving nuclear spins in substrate. The coherence time measured using dynamical decoupling extends up to $\approx$ 400 $μ$s for 128 decoupling pulses, with no sign of saturation. We find evidence that the coherence time is limited by noise in the 10 kHz $-$ 1 MHz range, possibly because charge noise affecting the spin via the micromagnet gradient. This work shows that an electron spin in a Si/SiGe quantum dot is a good candidate for quantum information processing as well as for a quantum memory, even without isotopic purification.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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