Topologically nontrivial Floquet band structure in a system undergoing photonic transitions in the ultrastrong-coupling regime
Topologically nontrivial Floquet band structure in a system undergoing photonic transitions in the ultrastrong-coupling regime
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DOI：
10.1103/physreva.92.053822
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发表时间：
2015-11-09
影响因子：
2.9
通讯作者：
Fan, Shanhui
中科院分区：
文献类型：
--
作者：
Yuan, Luqi;Fan, Shanhui
我们考虑了一个经过光子跃迁的动态调制光子谐振腔晶格系统，并证明了在超强耦合状态下，这样的晶格可以表现出非平凡的拓扑性质，包括拓扑非平凡带隙和相关的拓扑鲁棒单向边缘态。与在旋转波近似有效的情况下工作的相同系统相比，在超强耦合情况下工作的系统产生的单向边缘模式具有更大的带宽，并且不易受损耗影响。此外，在超强耦合状态下，随着调制强度的变化，系统经历了拓扑绝缘体到金属的相变。这种相变在满足旋转波近似的系统中没有对应的相变，其性质与准能量空间的非平凡拓扑直接相关。
We consider a system of dynamically-modulated photonic resonator lattice undergoing photonic transition and show that in the ultrastrong-coupling regime such a lattice can exhibit nontrivial topological properties, including topologically nontrivial band gaps, and the associated topologically robust one-way edge states. Compared with the same system operating in the regime where the rotating wave approximation is valid, operating the system in the ultrastrong-coupling regime results in a one-way edge mode that has a larger bandwidth and is less susceptible to loss. Also, in the ultrastrong-coupling regime, the system undergoes a topological insulator-to-metal phase transition as one varies the modulation strength. This phase transition has no counterpart in systems satisfying the rotating wave approximation, and its nature is directly related to the nontrivial topology of the quasienergy space.