标题： 光子从多能级量子发射器系统散射。 II. 应用于耦合到一维波导的发射器 显示英文标题

标题： Photon Scattering from a System of Multi-Level Quantum Emitters. II. Application to Emitters Coupled to a 1D Waveguide

摘要： 在先前的一篇论文中，我们引入了一种形式化方法来研究低强度场从嵌入在 $3$D 介质中的多能级发射器系统散射的问题。 在这里，我们展示了如何利用这种光子散射关系来分析单光子和弱相干态从任何通用的多能级量子发射器耦合到 $1$D 波导时的散射。 将光子散射关系简化为 $1$D 波导，首次提供了在波导 QED 范畴内涉及低强度场的散射问题的直接解法。 为了展示我们的形式化方法是如何工作的，我们考虑了多能级发射器的例子，并计算了透射和反射场幅度。 此外，我们将研究扩展到包括发射器在弱相干光子脉冲散射中的动态响应。 由于我们的光子散射关系基于海森堡绘景，因此对于涉及波导结构中光子探测的问题非常有用。 我们通过考虑一个具体的多能级发射器中通过光子探测生成状态的问题来说明这一点，其中我们的形式化方法展现了其全部潜力。 由于所考虑的发射器是通用的， $1$D 的结果适用于大量物理系统，如原子、离子、量子点、超导量子位以及耦合到 $1$D 波导或传输线的氮空位中心。 显示英文摘要

摘要： In a preceding paper we introduced a formalism to study the scattering of low intensity fields from a system of multi-level emitters embedded in a $3$D dielectric medium. Here we show how this photon-scattering relation can be used to analyze the scattering of single photons and weak coherent states from any generic multi-level quantum emitter coupled to a $1$D waveguide. The reduction of the photon-scattering relation to $1$D waveguides provides for the first time a direct solution of the scattering problem involving low intensity fields in the waveguide QED regime. To show how our formalism works, we consider examples of multi-level emitters and evaluate the transmitted and reflected field amplitude. Furthermore, we extend our study to include the dynamical response of the emitters for scattering of a weak coherent photon pulse. As our photon-scattering relation is based on the Heisenberg picture, it is quite useful for problems involving photo-detection in the waveguide architecture. We show this by considering a specific problem of state generation by photo-detection in a multi-level emitter, where our formalism exhibits its full potential. Since the considered emitters are generic, the $1$D results apply to a plethora of physical systems like atoms, ions, quantum dots, superconducting qubits, and nitrogen-vacancy centers coupled to a $1$D waveguide or transmission line.