里德堡极化激元的相干增强
Coherence enhancement of Rydberg polaritons
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中文总结 AI 辅助
研究针对里德堡极化激元快速运动退相干问题，设计通过让原子记速度或根据存储时间改相位来增强相干性的方案，经特定协议及中间态选择使检索时相位相干，数值计算显示能几乎完全消除运动退相，推动相关量子光学应用。
中文摘要 AI 辅助
里德堡极化激元的量子非线性光学可实现单光子晶体管与开关、单光子源及确定性量子信息处理。本研究的主要障碍是快速运动退相干。我们设计了一种方案，通过让原子‘记住’其速度，或根据里德堡极化激元的存储时间‘改变’其相位，显著增强里德堡极化激元的相干性。制备里德堡极化激元后，两个激光场通过一个大幅失谐的低能中间态诱导其在两个里德堡态间跃迁。特定协议及中间态选择可使检索时的里德堡极化激元相位相干，数值计算表明该理论几乎能完全消除运动退相，为里德堡介导的量子非线性光学广泛应用提供思路。
英文摘要
Quantum nonlinear optics by Rydberg polaritons can enable single-photon transistor and switch, single-photon source, and deterministic quantum information processing. A major hindrance in this study is the fast motional decoherence. Here, we devise a scheme to significantly enhance the coherence of Rydberg polariton by letting the atoms {\it remember} their velocities, or, alternatively, by {\it changing} the phase of Rydberg polariton according to its storage time. After the Rydberg polariton is prepared with a Rydberg state $|r_1\rangle$, i.e., during the storage time, two laser fields induce a transition between $|r_1\rangle$ and a nearby Rydberg state $|r_2\rangle$ via a low-lying intermediate state $\lvert f\rangle$ which is largely detuned. In particular, we find that either a $2π\mathbb{N}$ protocol, a $π$-wait-$π$ protocol, or a wait-$π$ protocol, along with an appropriate choice of $\lvert f\rangle$ can lead to a phase-coherent Rydberg polariton upon its retrieval. Importantly, the coherent transition between $|r_1\rangle$ and $|r_2\rangle$ ensures that the Rydberg polariton can block the Rydberg excitation of nearby atoms as in usual applications of Rydberg polaritons. Numerics show that the theory can nearly completely eliminate the motional dephasing, leaving Rydberg-state decay as the only fundamental channel of decoherence. This sheds light on a broad application of Rydberg-mediated quantum nonlinear optics.
