We study the interaction between a topological insulator nanoparticle and a quantum dot subject to an applied electric field. The electromagnetic response of the topological insulator is derived from axion electrodynamics in the quasistatic approximation. Localized modes are quantized in terms of dipolar bosonic modes, which couples dipolarly to the quantum dot. Hence, we treat the hybrid as a two-level system interacting with a single bosonic mode, where the coupling strength encodes the information concerning the nontrivial topology of the nanoparticle. The interaction of the hybrid with the environment is implemented through the coupling with a continuum reservoir of radiative output modes and a reservoir of phonon modes. In particular, we use the method of Zubarev’s Green functions to derive an expression for the optical absorption spectrum of the system. We apply our results to a realistic system which consists of a topological insulator nanoparticle made of TlBiSe${}_2$ interacting with a Cadmium Selenide (CdSe) quantum dot, both immersed in a polymer layer such as poly(methyl methacrylate). The optical absorption spectrum exhibits Fano resonances with a line shape that strongly depends on the polarization of the electric field as well as on the topological magnetoelectric polarizability $\theta$. Our results and methods can also be applied to nontopological magnetoelectric materials such as Cr${}_2$O${}_3$.

中文翻译：

---

拓扑-绝缘体-量子点混合体与探针电场相互作用的光学响应

我们研究了拓扑绝缘体纳米粒子与受外加电场作用的量子点之间的相互作用。拓扑绝缘子的电磁响应来自准静态近似中的轴电动力学。局部模式是根据偶极玻色子模式量化的，它偶极耦合到量子点。因此，我们将杂化体视为与单个玻色子模式相互作用的两级系统，其中耦合强度编码有关纳米粒子非平凡拓扑结构的信息。混合动力汽车与环境的相互作用是通过与辐射输出模式的连续储库和声子模式的储库耦合实现的。尤其是，我们使用Zubarev格林函数的方法来推导系统的光吸收光谱的表达式。我们将结果应用于由TlBiSe制成的拓扑绝缘体纳米粒子组成的现实系统${}_2$与硒化镉（CdSe）量子点相互作用，二者均浸在聚合物层中，例如聚甲基丙烯酸甲酯。光吸收光谱表现出线型的Fano共振，该线形强烈取决于电场的极化以及拓扑磁电极化率$\theta$。我们的结果和方法也可以应用于非拓扑磁电材料，例如Cr${}_2$Ø${}_3$。