量子相干反馈调控巨原子自发辐射动力学  

Spontaneous emission dynamics of giant atom controlled by quantum coherent feedback

作　　者：程木田 蔡国庆 马小三 CHENG MuTian;CAI GuoQing;MA XiaoSan(School of Electrical Engineering&Information,Anhui University of Technology,Ma’anshan 243002,China)

机构地区：[1]安徽工业大学电气与信息工程学院,马鞍山243002

出　　处：《中国科学：物理学、力学、天文学》2023年第11期155-164,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:119075023);国家重点研发计划(编号:2018YFB601402);安徽省教育厅科学研究项目(重大)(编号:2022AH040053);安徽省高校优秀青年人才支持计划重点项目(编号:gxyqZD2020014)资助。

摘　　要：本文研究了单个巨原子与半无限波导耦合的自发辐射动力学特性.通过薛定谔方程,得到原子激发态概率振幅随时间演化的延时动力学方程.在非马尔可夫条件下,分别讨论了巨原子与波导两个耦合点耦合系数全同以及存在相位差时,由半无限波导及其边界形成的量子相干反馈对巨原子自发辐射的动力学调控.由于反馈造成巨原子被多次激发,其自发辐射动力学展现了多段性.耦合系数全同时,通过量子反馈可以使得巨原子加快或抑制激发态衰减速率,甚至达到稳态值.耦合系数存在相位差时,通过控制相位差,也可以实现加快或减慢巨原子衰减速率以及达到稳态值.本文还讨论了巨原子耗散对辐射动力学的影响.相关结果对开发基于巨原子光量子器件如量子存储器等方面具有潜在的应用价值.We investigated the spontaneous emission of a giant atom coupled with a semi-infinite waveguide.Our model considers the giant atom a two-level system coupled to the semi-infinite waveguide at two points.Based on the Hamiltonian in real space,the first-order delay-differential equation for the atomic excitation amplitude is obtained using the Schrödinger equation.Furthermore,the dynamics of spontaneous emission controlled by quantum coherent feedback due to the semiinfinite waveguide in the non-Markov regime are discussed in two cases,with the coupling strengths between the giant atom and the semi-infinite waveguide at the two coupling points being identical in one case and having a phase difference in the other case.The spontaneous emission exhibits partial decay due to multiple excitations from the quantum feedback and two-point coupling.When the coupling strengths are identical,the decay of the atomic excitation can be either increased or inhibited substantially,even forming a steady state,due to the self-interference due to the two-point coupling.The quantum coherent feedback can either further increase the decay of the excited state or maintain the steady state formed by self-interference.Moreover,a new steady state can be built due to quantum coherent feedback,which cannot exist in the self-interference system.The decay rates can also be increased or decreased by manipulating the phase difference between the coupling strengths at the two coupling points.It can destroy the steady state formed by selfinterference or build a steady state based on the chosen phase difference.One can leverage quantum coherent feedback to manipulate the steady state value of the population of the excited states by adjusting the phase difference.The dissipation can increase the decay rates of the excited states.Furthermore,it also destroys steady states.Our results may find applications in developing quantum devices such as quantum memory based on giant atom-waveguide systems.

关 键 词：巨原子 量子相干反馈 自发辐射 

分 类 号：O431.2[机械工程—光学工程]