Topological matter and topological optics have been studied in many systems, with promising applications in materials science and photonics technology. These advances motivate the study of the interaction between topological matter and light, as well as topological protection in light-matter interactions. In this work, we study a waveguide-interfaced topological atom array. The light-matter interaction is nontrivially modified by topology, yielding optical phenomena. We find topology-enhanced photon absorption from the waveguide for a large Purcell factor, i.e., $\mathrm{\Gamma }/{\mathrm{\Gamma }}_0\gg 1$, where $\mathrm{\Gamma }$ and ${\mathrm{\Gamma }}_0$ are the atomic decays to the waveguide and environment, respectively. To understand this unconventional photon absorption, we propose a multichannel scattering approach and study the interaction spectra for edge- and bulk-state channels. We find that, by breaking inversion and time-reversal symmetries, optical anisotropy is enabled for the reflection process, but the transmission is isotropic. Through a perturbation analysis of the edge-state channel, we show that the anisotropy in the reflection process originates from the waveguide-mediated non-Hermitian interaction. However, the inversion symmetry in the non-Hermitian interaction makes the transmission isotropic. At a topology-protected atomic spacing, the subradiant edge state exhibits huge anisotropy. Because of the interplay between edge- and bulk-state channels, a large topological bandgap enhances nonreciprocal reflection of photons in the waveguide for weakly broken time-reversal symmetry, i.e., ${\mathrm{\Gamma }}_0/\mathrm{\Gamma }\ll 1$, producing complete photon absorption. We show that our proposal can be implemented in superconducting quantum circuits. The topology-enhanced photon absorption is useful for quantum detection. This work shows the potential to manipulate light with topological quantum matter.

中文翻译：

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波导中的拓扑增强的不可逆散射和光子吸收

拓扑物质和拓扑光学已经在许多系统中得到了研究，在材料科学和光子学技术中具有广阔的应用前景。这些进展促进了拓扑物质与光之间相互作用的研究，以及光物质相互作用中的拓扑保护。在这项工作中，我们研究了波导界面拓扑原子阵列。光与物质的相互作用不会被拓扑结构轻易地改变，从而产生光学现象。我们发现，对于较大的赛尔因数，即从波导获得的拓扑增强的光子吸收，即$\mathrm{\Gamma }/{\mathrm{\Gamma }}_0\gg \mathrm{1个}$， 在哪里 $\mathrm{\Gamma }$ 和 ${\mathrm{\Gamma }}_0$是分别衰减到波导和环境的原子。为了理解这种非常规的光子吸收，我们提出了一种多通道散射方法，并研究了边缘和本体状态通道的相互作用谱。我们发现，通过打破反演和时间反转的对称性，光学各向异性可以用于反射过程，但是透射是各向同性的。通过对边缘状态通道的扰动分析，我们表明反射过程中的各向异性源于波导介导的非赫米特相互作用。但是，非Hermitian相互作用中的反演对称性使传输各向同性。在受拓扑保护的原子间距下，亚辐射边缘态表现出巨大的各向异性。由于边缘状态通道和体态通道之间的相互作用，${\mathrm{\Gamma }}_0/\mathrm{\Gamma }\ll \mathrm{1个}$，产生完全的光子吸收。我们证明了我们的建议可以在超导量子电路中实现。拓扑增强的光子吸收对于量子检测很有用。这项工作显示了利用拓扑量子物质操纵光的潜力。