无限长矩形波导中二能级原子的自发辐射  

Spontaneous Emission of a Two-level Atom in an Infinite Rectangular Waveguide

作　　者：刘延 李梦薇 甄灵敏 宋亚菊 Liu Yan;Li Mengwei;Zhen Lingmin;Song Yaju(College of Physics and Electronic Engineering,Hengyang Normal University,Hengyang Hunan 421002,China)

机构地区：[1]衡阳师范学院物理与电子工程学院,湖南衡阳421002

出　　处：《衡阳师范学院学报》2020年第6期56-59,共4页Journal of Hengyang Normal University

基　　金：湖南省自然科学基金青年项目(2019JJ50007);衡阳师范学院科研启动项目(17D18)。

摘　　要：波导量子电动力学是实现量子网络的理想方案之一,而自发辐射导致的退相干是阻碍其发展的主要因素。该文以矩形波导为例,研究在受限空间中二能级原子的自发辐射特性。通过利用Lippmann-Schwinger方程和不含时薛定谔方程推导出矩形波导与二能级原子耦合系统的本征散射态和本征束缚态,进而求得时间演化算符和原子的自发辐射动力学。研究表明,原子的自发辐射特性主要由原子与矩形波导的失谐量和耦合强度决定。与自由空间相比,矩形波导具有非线性色散关系,由此诱导的束缚态会导致稳态相干现象。该研究为在波导量子电动力学系统中实现量子网络提供了重要的理论指导。Waveguide quantum electrodynamics is an ideal scheme for realizing quantum network,and the decoherence caused by spontaneous radiation is the main obstacle.In this paper,we take the rectangular waveguides as an example to study the spontaneous emission of a two-level atom in confined space.By using the Lippmann-Schwinger equation and the time-independent Schrodinger equation,the scattering and bound eigenstates of the coupled system are obtained.Then the time evolution operator and the dynamical evolution of the atomic spontaneous radiation are derived.It is found that the atomic spontaneous emission is mainly determined by the detuning and the coupling strength between atom and rectangular waveguide.Compared with the free space case,there exists the steady-state coherence due to the presence of the bound state,which is caused by the nonlinear dispersion relation of the rectangular waveguide.Our result provides important theoretical guidance for the realization of quantum networks in waveguide quantum electrodynamics systems.

关 键 词：自发辐射 无限长矩形波导 二能级原子 束缚态 散射态 

分 类 号：O413[理学—理论物理]