Quantum non-demolition readout of an electron spin in silicon
Quantum non-demolition readout of an electron spin in silicon
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DOI：
10.1038/s41467-020-14818-8
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发表时间：
2020-03
影响因子：
16.6
通讯作者：
J. Yoneda;K. Takeda;A. Noiri;T. Nakajima;S. Li;J. Kamioka;T. Kodera;S. Tarucha
中科院分区：
文献类型：
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作者：
J. Yoneda;K. Takeda;A. Noiri;T. Nakajima;S. Li;J. Kamioka;T. Kodera;S. Tarucha
虽然硅自旋量子位的单次检测现在已成为实验室常规，但大规模量子计算设备中的量子纠错需要实现量子不可拆除（QND）。与传统的对应物不同，QND 自旋读数对探测的自旋极化施加最小的干扰，因此可以重复以消除测量误差。在这里，我们表明，通过探测与量子位自旋耦合的相邻点中的另一个电子自旋，可以以高度非破坏的方式测量硅中的电子自旋量子位。高非破坏保真度（平均 99%）可实现单个旋转状态的 20 多次重复读出，从而在 1.2 毫秒内产生高达 95% 的总体平均测量保真度。我们进一步证明我们的重复 QND 读出协议可以实现预示的高保真度 (>99.6%) 基态准备。我们基于 QND 的测量和准备，由第二个同类量子位介导，将允许在硅中使用电子自旋的多种量子信息协议，而不会影响架构的同质性。
While single-shot detection of silicon spin qubits is now a laboratory routine, the need for quantum error correction in a large-scale quantum computing device demands a quantum non-demolition (QND) implementation. Unlike conventional counterparts, the QND spin readout imposes minimal disturbance to the probed spin polarization and can therefore be repeated to extinguish measurement errors. Here, we show that an electron spin qubit in silicon can be measured in a highly non-demolition manner by probing another electron spin in a neighboring dot Ising-coupled to the qubit spin. The high non-demolition fidelity (99% on average) enables over 20 readout repetitions of a single spin state, yielding an overall average measurement fidelity of up to 95% within 1.2 ms. We further demonstrate that our repetitive QND readout protocol can realize heralded high-fidelity (>99.6%) ground-state preparation. Our QND-based measurement and preparation, mediated by a second qubit of the same kind, will allow for a wide class of quantum information protocols with electron spins in silicon without compromising the architectural homogeneity.