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arXiv 1407.8074quant-phcond-mat.mes-hall
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利用邻域最优控制提高量子门性能

Improving quantum gate performance through neighboring optimal control

Yuchen Peng, Frank Gaitan

摘要:

在量子比特系统上成功实现容错量子计算对用于控制多量子比特状态的硬件提出了严格的要求。已知对于要在这样的计算中使用的任何量子门存在准确度阈值$P_{a}$。具体地说,这种门的错误概率$P_{e}$必须低于精度阈值:$P_{e} < P_{a}$。尽管$P_{a}\sim 10^{-4}$已成为硬件设计人员的一个具有挑战性的目标,但对$P_{a}$的估计差异很大。在本文中,我们提出了一个理论框架的基础上相邻的最优控制,作为输入的一个好的量子门,并返回一个新的门具有更好的性能。我们说明了这种方法,将其应用到所有的门在一个通用的一组量子门使用非绝热快速通过,已出现在文献中。性能改进是实质性的,无论是理想的和非理想的控制。在下面详细描述的合适条件下,所有门错误概率都远低于$10^{-4}$的目标阈值。

英文摘要:

Successful implementation of a fault-tolerant quantum computation on a system of qubits places severe demands on the hardware used to control the many-qubit state. It is known that an accuracy threshold $P_{a}$ exists for any quantum gate that is to be used in such a computation. Specifically, the error probability $P_{e}$ for such a gate must fall below the accuracy threshold: $P_{e} < P_{a}$. Estimates of $P_{a}$ vary widely, though $P_{a}\sim 10^{-4}$ has emerged as a challenging target for hardware designers. In this paper we present a theoretical framework based on neighboring optimal control that takes as input a good quantum gate and returns a new gate with better performance. We illustrate this approach by applying it to all gates in a universal set of quantum gates produced using non-adiabatic rapid passage that has appeared in the literature. Performance improvements are substantial, both for ideal and non-ideal controls. Under suitable conditions detailed below, all gate error probabilities fall well below the target threshold of $10^{-4}$.

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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