论文标题
纳米纤维腔量子电动力学系统中的高阶特殊点
High-order exceptional point in a nanofiber cavity quantum electrodynamics system
论文作者
论文摘要
我们提出了一个全纤维发射极腔量子电动力学（QED）系统，该系统由两个两级发射器和一个纳米纤维腔组成。我们的方案使基于发射器与纳米纤维腔之间的耦合观察高阶特殊点成为可能。该腔的有效增益可以通过通过两个相同的激光场弱驱动到纳米纤维腔来获得，这将实现实验实现时连贯的完美吸收（CPA）。在实验性可行参数下，该系统的哈密顿量是伪热的条件，这意味着其特征值可以由一对真实和一对复杂的偶联物制成，也可以是真实的。通过可控制地调整了两个发射极腔耦合强度的比率，以及发射器的衰减速率的比率，我们可以在我们的Emitter-cavity系统中同时发现三阶异常点（EP3）和二阶特殊点（EP3）而无需偶然时间对称。这些结果也可以通过总输出光谱和传输光谱来证明。我们还发现，当耦合强度大于EP3点处的临界耦合强度时，对称模式就会出现。我们的建议将提供一种新方法来实现高阶特殊点。
We present an all-fiber emitter-cavity quantum electrodynamics (QED) system which consists of two two-level emitters and a nanofiber cavity. Our scheme makes it possible to observe the higher-order exceptional points based on the coupling between the emitters and the nanofiber cavity. The effective gain of this cavity can be obtained by weakly driven to the nanofiber cavity via two identical laser fields, which will realize coherent perfect absorption (CPA) in the implementation of the experiments. Under the experimental feasible parameters, the Hamiltonian of this system is in the condition of pseudo-Hermiticity, which means that its eigenvalues can be made of one real and a pair of complex conjugates, or be all real. By controllably tuned the ratio of the two emitter-cavity coupling strengths, and the ratio of the decay rates of the emitters, we can discover both the three-order exceptional point (EP3) and the second-order exceptional point (EP2) without parity-time symmetry in our emitter-cavity system. These results can also be demonstrated by the total output spectra and transmission spectra. We also find that the symmetric modes come into being when the coupling strength greater than the critical coupling strength at EP3 points. Our proposal will provide a new method to realize higher-order exceptional points.
