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arXiv 2209.11643quant-ph
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稳定对相干态的实验实现与表征

Experimental Realization and Characterization of Stabilized Pair Coherent States

Jeffrey M. Gertler, Sean van Geldern, Shruti Shirol, Liang Jiang, Chen Wang

摘要:

对相干态(PCS)是Glauber相干态到两个谐振子的理论推广。它是一类有趣的非高斯连续变量纠缠态,也是一种很有前途的量子纠错码:对猫码的核心。本文报道了微波光子在两个超导腔中的成对相干态的实验演示。我们实现了一个跨腔双光子驱动的耗散过程,它保持了腔之间的光子数差,并将状态稳定到一个特定的复振幅。我们进一步介绍了一种量子子空间层析成像技术,该技术可以直接测量高维量子态的单个相干元素,而无需全局层析重建。我们的特点是我们的双模量子态与多达4个光子在每个腔使用这个子空间层析成像与直接测量的光子数差和联合维格纳函数。我们确定的寄生腔和我们的耗散水库模式之间的交叉克尔相互作用作为一个突出的退相通道,限制了我们目前的计划中的稳态相干。我们的实验为研究量子光学和在超导电路中实现多模玻色子码提供了一套库工程和状态表征工具。

英文摘要:

The pair coherent state (PCS) is a theoretical extension of the Glauber coherent state to two harmonic oscillators. It is an interesting class of non-Gaussian continuous-variable entangled state and is also at the heart of a promising quantum error correction code: the pair cat code. Here we report an experimental demonstration of the pair coherent state of microwave photons in two superconducting cavities. We implement a cross-cavity pair-photon driven dissipation process, which conserves the photon number difference between cavities and stabilizes the state to a specific complex amplitude. We further introduce a technique of quantum subspace tomography, which enables direct measurements of individual coherence elements of a high-dimensional quantum state without global tomographic reconstruction. We characterize our two-mode quantum state with up to 4 photons in each cavity using this subspace tomography together with direct measurements of the photon number difference and the joint Wigner function. We identify the spurious cross-Kerr interaction between the cavities and our dissipative reservoir mode as a prominent dephasing channel that limits the steady-state coherence in our current scheme. Our experiment provides a set of reservoir engineering and state characterization tools to study quantum optics and implement multi-mode bosonic codes in superconducting circuits.

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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