论文标题
评估近期光子量子设备的质量
Assessing the quality of near-term photonic quantum devices
论文作者
论文摘要
对于近期量子设备，一个重要的挑战是开发有效的方法，以证明噪声水平足够低，以允许进行潜在有用的应用程序。我们提出了一种针对光子量子设备量身定制的方法，该方法由单个光子源组成，并耦合到线性光学电路与光子检测器耦合。它使用玻色带采样实验的输出统计信息，其中输入尺寸$ n $（$ n $输入光子在理想情况下）。我们提出了一系列针对两个主要噪声来源的基准测试，即光子丧失和区分性。我们的方法导致单数度量，即光子质量因子，定义为输入统计量通过所有测试的输入光子数量最多。我们提供了有力的证据表明，通过所有测试意味着我们的实验在经典上无法有效地模拟，这是通过显示几种现有的经典算法如何有效地模拟嘈杂的肺泡采样使测试失败。最终，我们表明，在任何两个单个光子状态之间，每个模式平均每模式的平均光子损耗率为$ O（1）$和平均保真度为$（1-O（\ frac {1} {N^6}））^2 $在任何两个单个光子状态之间足以继续通过我们的测试。毫不奇怪，我们的结果表明，以避免有效的经典模拟性的方式进行缩放在某个时候必须需要纠正和缓解。
For near-term quantum devices, an important challenge is to develop efficient methods to certify that noise levels are low enough to allow potentially useful applications to be carried out. We present such a method tailored to photonic quantum devices consisting of single photon sources coupled to linear optical circuits coupled to photon detectors. It uses the output statistics of BosonSampling experiments with input size $n$ ($n$ input photons in the ideal case). We propose a series of benchmark tests targetting two main sources of noise, namely photon loss and distinguishability. Our method results in a single-number metric, the Photonic Quality Factor, defined as the largest number of input photons for which the output statistics pass all tests. We provide strong evidence that passing all tests implies that our experiments are not efficiently classically simulable, by showing how several existing classical algorithms for efficiently simulating noisy BosonSampling fail the tests. Finally we show that BosonSampling experiments with average photon loss rate per mode scaling as $o(1)$ and average fidelity of $ (1-o(\frac{1}{n^6}))^2$ between any two single photon states is sufficient to keep passing our tests. Unsurprisingly, our results highlight that scaling in a manner that avoids efficient classical simulability will at some point necessarily require error correction and mitigation.
