周期驱动对光学系统Parity-Time对称性的调控

In this project, we will conduct theoretical study on the topics of how to employ periodic modulations to manipulate Parity-Time (PT) symmetry in optical systems. Our planned projects include: First, we will present an analysis of the driven PT optical system in a more accurate way by a multiple scale asymptotic expansion method. This more accurate method allows us to predict some novel and important physical phenomenon which is easily neglected in the exactly numerical simulations and totally lost in the commonly used high-frequency averaging approximation. Second, we will explore the combined effects of nonlinearity, periodic driving and PT symmetry on the system's dynamics. Third, we will propose some experimental schemes to observe and demonstrate the berry phase and its applications in driven PT optical systems. Our work is of broad interest as the underlying idea may become fruitful in other ?elds, and promises versatile applications in quantum technology and optical device.

本项目基于Floquet态理论和多重尺度微扰法研究如何利用周期驱动调控光学系统的Parity-Time（PT）对称性。利用更高阶的近似分析方法揭示和预言一些容易被忽视的新的量子现象，为设计光学器件提供理论依据；探索非线性、维度、周期驱动、PT对称性等相互作用下的系统动力学机制；直观理解PT对称性系统中的几何相位，阐明非厄密系统中的几何相位在耦合光波导中的观测效应和应用。本项目开展的理论研究不仅有助于人们理解周期驱动系统的PT概念，而且在量子技术、光学通信和冷原子领域有着潜在的应用价值。

本项目利用数值模拟和分析方法研究了周期驱动对光学系统中的Parity-time对称调控。主要研究内容包括：（1）构造了一类周期驱动的非线性的PT系统的精确解，这类精确解的获得不但可以用来证明非线性诱导的PT破缺到PT对称的转变，对理解含时非线性系统的PT对称性也有所帮助；（2）获得了另外一类同步驱动控制下的PT两能级系统的精确解，此类精确解加深和丰富了我们对相干隧穿破坏（CDT）和相干布局反转（CPI）这两个原本在厄米系统中发现和应用的量子现象的理解，拓展了这两个著名的量子现象在非厄米系统中的应用。