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arXiv 2008.11054quant-ph
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实验量子退火中的搜索范围

Search range in experimental quantum annealing

Nicholas Chancellor, Viv Kendon

摘要:

我们构建了一个伊辛哈密顿与工程能源景观,使它有一个本地的能量最小值,这是接近真正的全球最小值的解决方案,并进一步远离假最小值。使用在以前的实验中建立的技术,我们设计我们的实验,使得(至少在与我们的研究相关的时间尺度上)由于高水平的量子涨落,在正向退火中优先达到假最小值。这使我们能够证明反向退火的关键原理,即可以在局部搜索解空间,优先找到附近的解,即使存在假最小值。据我们所知,这里使用的技术与以前使用的实验技术不同,并允许我们以一种以前没有探索过的方式探测设备的基本搜索范围。我们在两个通量量子比特量子退火机上进行了这些实验,其中一个具有比另一个更高的噪声水平。我们发现证据表明,低噪声设备更有可能找到更远的能量最小值(在这种情况下是假最小值),这表明降低噪声从根本上增加了通量量子比特量子退火器能够搜索的范围。我们的工作解释了为什么降低噪声会提高这些量子退火机的性能。这支持了这样一种想法,即这些设备可能能够快速搜索解决方案空间的广泛区域,这是量子退火器被视为量子计算优势的潜在途径的核心原因之一。

英文摘要:

We construct an Ising Hamiltonian with an engineered energy landscape such that it has a local energy minimum which is near to the true global minimum solution, and further away from a false minimum. Using a technique established in previous experiments, we design our experiment such that (at least on timescales relevant to our study) the false minimum is reached preferentially in forward annealing due to high levels of quantum fluctuations. This allows us to demonstrate the key principle of reverse annealing, that the solution space can be searched locally, preferentially finding nearby solutions, even in the presence of a false minimum. The techniques used here are, to the best of our knowledge, distinct from previously used experimental techniques, and allow us to probe the fundamental search range of the device in a way which has not been previously explored. We perform these experiments on two flux qubit quantum annealers, one with higher noise levels than the other. We find evidence that the lower noise device is more likely to find the more distant energy minimum (the false minimum in this case), suggesting that reducing noise fundamentally increases the range over which flux qubit quantum annealers are able to search. Our work explains why reducing the noise leads to improved performance on these quantum annealers. This supports the idea that these devices may be able to search over broad regions of the solution space quickly, one of the core reasons why quantum annealers are viewed as a potential avenue for a quantum computational advantage.

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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