Zhang Yuan, Wu Qilong, Su Shi-Lei, Lou Qing, Shan Chongxin, Mølmer Klaus
Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Daxue Road 75, Zhengzhou 450052, China.
Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark; Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
Phys Rev Lett. 2022 Jun 24;128(25):253601. doi: 10.1103/PhysRevLett.128.253601.
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.
腔量子电动力学（CQED）效应，如拉比分裂、拉比振荡和超辐射，已在低温下将金刚石中的氮空位（NV）中心自旋与微波谐振器耦合时得到证实。在本信函中，我们探索了在室温下利用NV自旋系综实现强集体耦合和CQED效应的可能性。我们的计算表明，单个NV自旋的热激发会导致具有低对称性的集体狄克态的布居，并降低与微波谐振器的集体耦合。光泵浦可用于抵消NV中心的热激发，并将自旋系综制备成具有高对称性的狄克态。由此产生的与高质量谐振器的强耦合使得能够研究跨越弱耦合到强耦合区域的有趣的CQED效应，并且可能在量子传感和量子信息处理中有应用。
