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arXiv 1502.03156cond-mat.mes-hall
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硅基量子点混合量子比特的高保真共振选通

High fidelity resonant gating of a silicon based quantum dot hybrid qubit

Dohun Kim, D. R. Ward, C. B. Simmons, D. E. Savage, M. G. Lagally, Mark Friesen, S. N. Coppersmith, Mark A. Eriksson

摘要:

半导体中的孤立自旋为探索量子力学相干性和开发工程量子系统提供了一个有前途的平台。硅由于其弱的自旋轨道耦合和超精细相互作用,作为开发自旋量子比特的主体材料引起了极大的兴趣,并且已经提出并实验证明了基于门定义量子点的几种结构。最近,人们提出了一种由双量子点中的三个电子组成的量子点混合量子比特,并在实验上实现了非绝热脉冲门操作,实现了简单快速的自旋态电操纵,且相干时间与操纵时间之比很有希望。然而,脉冲门控混合量子位的总体门保真度受到由于两个所需门操作之一期间的电荷噪声而导致的相对快速的失相的限制。在这里,我们执行的第一个微波驱动的栅极操作的量子点混合量子位,完全避免了制度,它是最敏感的电荷噪声。谐振失谐调制以及微波的相位控制使得围绕X(Z)轴的π旋转时间小于5 ns(50 ps),具有> 93(96)%的高结晶度。我们还实现了哈恩回波和卡尔-珀塞尔(CP)动态去耦序列,我们证明了超过150纳秒的相干时间。我们进一步讨论了一种将门保真度提高到99%以上的途径,超过了基于表面码的量子纠错的阈值。

英文摘要:

Isolated spins in semiconductors provide a promising platform to explore quantum mechanical coherence and develop engineered quantum systems. Silicon has attracted great interest as a host material for developing spin qubits because of its weak spin-orbit coupling and hyperfine interaction, and several architectures based on gate defined quantum dots have been proposed and demonstrated experimentally. Recently, a quantum dot hybrid qubit formed by three electrons in double quantum dot was proposed, and non-adiabatic pulsed-gate operation was implemented experimentally, demonstrating simple and fast electrical manipulations of spin states with a promising ratio of coherence time to manipulation time. However, the overall gate fidelity of the pulse-gated hybrid qubit is limited by relatively fast dephasing due to charge noise during one of the two required gate operations. Here we perform the first microwave-driven gate operations of a quantum dot hybrid qubit, avoiding entirely the regime in which it is most sensitive to charge noise. Resonant detuning modulation along with phase control of the microwaves enables a pi rotation time of less than 5 ns (50 ps) around X(Z)-axis with high fidelities > 93 (96) %. We also implement Hahn echo and Carr-Purcell (CP) dynamic decoupling sequences with which we demonstrate a coherence time of over 150 ns. We further discuss a pathway to improve gate fidelity to above 99 %, exceeding the threshold for surface code based quantum error correction.

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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