Recently, significant effort has been devoted to the study of atom–photon quantum interfaces using intracavity Rydberg-blocked atomic ensembles, which may serve as the platform for many essential quantum information processing tasks. In this paper, we use a theoretical analysis of this platform where the ground-Rydberg transition is realized by a two-photon transition, and we report our recent findings regarding the Jaynes–Cummings model on optical domain and robust atom–photon quantum gates. Our implementation with typical alkali atoms, such as Rb or Cs, requires an optical cavity of moderately high finesse and the condition that the cold atomic ensemble is well within the Rydberg-blockade radius. The analysis focuses on the atomic ensemble’s collective coupling to the quantized optical field in the cavity mode, and we demonstrate its capability to serve as a controlled-PHASE gate between photonic qubit and matter qubit, where the photonic qubit is endowed with a reasonably wide frequency tuning range. The detrimental effects associated with several major decoherence factors in this system are also considered in the analysis.

中文翻译：

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腔内里德堡阻挡的原子团通过双光子跃迁分析原子-光子量子界面

最近，人们已经投入大量精力来研究使用腔内里德堡阻挡的原子团的原子-光子量子界面，该原子团可以作为许多基本量子信息处理任务的平台。在本文中，我们使用该平台的理论分析，其中通过两个光子跃迁实现了地面-里德堡跃迁，并且我们报告了有关光域和鲁棒原子-光子量子门的Jaynes-Cummings模型的最新发现。我们使用典型的碱原子（例如Rb或Cs）实施时，需要一个具有中等高精细度的光学腔，并且条件是冷原子集合必须在Rydberg封锁半径之内。分析着重于在腔模中原子团对量子光场的集体耦合，并且我们证明了它能够用作光子量子位和物质量子位之间的受控相位门，其中光子量子位具有相当宽的频率调谐范围。分析中还考虑了与该系统中几个主要退相干因素相关的有害影响。