论文标题
无偏量子估计
Unbiased quantum phase estimation
论文作者
论文摘要
量子相估计算法（PEA）是量子计算早期研究中最重要的算法之一。它也是许多其他量子算法的关键，例如量子计数算法和Shor的整数分解算法。但是，我们发现PEA不是公正的估计，这阻止了估计误差达到任意级别的估计。在本文中，我们根据原始PEA提出了一种无偏的相估计算法（UPEA），并研究了其在量子计数中的应用。我们还表明，最大似然后处理步骤可以进一步改善其鲁棒性。最后，我们将UPEA应用于量子计数，并使用额外的校正步骤使量子计数算法无偏。
Quantum phase estimation algorithm (PEA) is one of the most important algorithms in early studies of quantum computation. It is also a key for many other quantum algorithms, such as the quantum counting algorithm and the Shor's integer factorization algorithm. However, we find that the PEA is not an unbiased estimation, which prevents the estimation error from achieving an arbitrarily small level. In this paper, we propose an unbiased phase estimation algorithm (UPEA) based on the original PEA, and study its application in quantum counting. We also show that a maximum likelihood post-processing step can further improve its robustness. In the end, we apply UPEA to quantum counting, and use an additional correction step to make the quantum counting algorithm unbiased.
