By employing the exact diagonalization method in and out of equilibrium, we investigate the half-filled spinless Haldane model on the honeycomb lattice with nearest-neighbor Coulomb repulsion. In equilibrium, the ground states with small and large interactions are in Chern insulator and charge-density-wave phase, respectively. Motivated by the recent study reporting a topologically nontrivial excited state in the strong coupling regime, we propose that such an underlying state can be detected by using optical conductivity in the open boundary condition. Specifically, we find that the dominant peak of the optical conductivity on edge is inside the bulk gap and its characteristic frequency is associated with the second excited state. Further analyses on the Drude peak indicate that the second excited state preserves a metallic edge even in the system away from the critical point. Meanwhile, it can be excited largely by not only circularly but also linearly polarized pump pulse. The latter is mostly overlooked by previous studies and implies that the polarization of the driving field is not so crucial to our system.

中文翻译：

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使用光导率检测相互作用 Haldane 模型中的底层金属边缘状态

通过使用平衡内外的精确对角化方法，我们研究了具有最近邻库仑排斥的蜂窝晶格上的半填充无旋霍尔丹模型。在平衡状态下，具有小相互作用和大相互作用的基态分别处于陈绝缘体和电荷密度波相。受最近研究报告强耦合状态中拓扑非平凡激发态的启发，我们建议可以通过在开放边界条件下使用光导率来检测这种潜在状态。具体而言，我们发现边缘光导率的主峰位于体隙内部，其特征频率与第二激发态相关。对德鲁德峰的进一步分析表明，即使在远离临界点的系统中，第二激发态也保留了金属边缘。同时，它不仅可以被圆极化的泵浦脉冲激发，还可以被线性极化的泵浦脉冲激发。后者在以前的研究中大多被忽视，这意味着驱动场的极化对我们的系统并不是那么重要。