Cavity quantum electrodynamics (CQED) effects, such as Rabi splitting, Rabi oscillations, and superradiance, have been demonstrated with nitrogen vacancy (NV) center spins in diamond coupled to microwave resonators at cryogenic temperature. In this Letter, we explore the possibility to realize strong collective coupling and CQED effects with ensembles of NV spins at room temperature. Our calculations show that thermal excitation of the individual NV spins leads to population of collective Dicke states with low symmetry and a reduced collective coupling to the microwave resonators. Optical pumping can be applied to counteract the thermal excitation of the NV centers and to prepare the spin ensemble in Dicke states with high symmetry. The resulting strong coupling with high-quality resonators enables the study of intriguing CQED effects across the weak-to-strong coupling regime, and may have applications in quantum sensing and quantum information processing.

中文翻译：

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与室温微波谐振器耦合的氮空位中心自旋的腔量子电动力学效应

腔量子电动力学 (CQED) 效应，如拉比分裂、拉比振荡和超辐射，已经在低温下与微波谐振器耦合的金刚石中的氮空位 (NV) 中心自旋得到证明。在这封信中，我们探讨了在室温下通过 NV 自旋集合实现强集体耦合和 CQED 效应的可能性。我们的计算表明，单个 NV 自旋的热激发导致具有低对称性的集体 Dicke 态的数量以及与微波谐振器的集体耦合减少。光泵浦可用于抵消 NV 中心的热激发并制备具有高对称性的 Dicke 态的自旋系综。