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arXiv 1902.01460quant-ph
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多模非高斯量子态工程中高斯态的有效表示方法

Efficient representation of Gaussian states for multi-mode non-Gaussian quantum state engineering via subtraction of arbitrary number of photons

Christos Gagatsos, Saikat Guha

摘要:

我们介绍了一个完整的描述多模玻色子量子态的相干态的基础上(在这项工作中表示为"$K$"功能),这-到一个阶段-是著名的胡西米"$Q$"表示的平方根。我们将任意$N$模高斯态的$K$函数表示为协方差矩阵和位移矢量的函数,并将一般连续变量团簇态的$K$函数表示为团簇的模压缩和图形拓扑的函数.这种形式主义让我们表征的非高斯状态遗留下来的,当一个测量的高斯状态的模式的子集使用光子数分辨检测,所获得的非高斯状态的保真度与任何目标状态,以及相关的预示概率,所有分析。我们表明,这种概率可以表示为一个哈夫尼,重新解释电路的输出状态声称证明量子霸权称为高斯玻色子采样。作为一个例子,我们的形式主义的应用,我们提出了一种方法来准备一个双模相干猫基础贝尔态的保真度接近统一和成功的概率,从根本上高于一个众所周知的计划,分裂近似单模猫态-通过光子数减法压缩真空模式-平衡分束器。这种形式主义可以使探索有效地产生猫基纠缠态,这是已知的是有用的量子纠错对光子损失。

英文摘要:

We introduce a complete description of a multi-mode bosonic quantum state in the coherent-state basis (which in this work is denoted as "$K$" function ), which---up to a phase---is the square root of the well-known Husimi "$Q$" representation. We express the $K$ function of any $N$-mode Gaussian state as a function of its covariance matrix and displacement vector, and also that of a general continuous-variable cluster state in terms of the modal squeezing and graph topology of the cluster. This formalism lets us characterize the non Gaussian state left over when one measures a subset of modes of a Gaussian state using photon number resolving detection, the fidelity of the obtained non-Gaussian state with any target state, and the associated heralding probability, all analytically. We show that this probability can be expressed as a Hafnian, re-interpreting the output state of a circuit claimed to demonstrate quantum supremacy termed Gaussian boson sampling. As an example-application of our formalism, we propose a method to prepare a two-mode coherent-cat-basis Bell state with fidelity close to unity and success probability that is fundamentally higher than that of a well-known scheme that splits an approximate single-mode cat state---obtained by photon number subtraction on a squeezed vacuum mode---on a balanced beam splitter. This formalism could enable exploration of efficient generation of cat-basis entangled states, which are known to be useful for quantum error correction against photon loss.

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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