周期性驱动系统的非平衡量子相变研究

With the rapid development of the newly emerged quantum engineering, how to realize the efficient control to single-quantum-state of microscopic systems has become one of the frontier issues in this field. We propose in this project to realize such control by use of the periodic driving. Explicitly, we are interested in exploring the role of the periodic driving in inducing novel quantum phase transition to the relevant quantum many-body systems. Different to the static system, whose quantum phase transition is characterized by its ground-state energy, the quantum phase transition of the periodically driven system as a non-equilibrium energy-non-conserved system is characterized by the Floquet quasienergy spectrum. Using this Floquet method, we will study in this project the novel role of the periodic driving played in the following three physical systems: 1) The non-equilibrium quantum phase transition in the periodically driven dissipative two-level system and its role in suppressing the decoherence; 2) The non-equilibrium quantum phase transition in the periodically driven Dicke model and its role in violating the superradiance "no-go theorem". 3) The novel non-equilibrium topological phase transition in periodically driven one-dimensional Kitaev model and two-dimensional Haldane model and its role in simulating the Majorana Fermion and the fractional quantum Hall effect in such lattice model. With these studies, we expect to reveal the application perspective of the periodic driving as an efficient control method in the rapidly developing quantum engineering field.

随着量子工程的不断发展，如何更加有效地调控单量子态已成为目前量子物理研究的一个前沿问题。本项目提出利用周期性驱动的手段对相关物理系统进行调控；探索该调控对系统量子相变的影响；揭发周期性驱动所诱发的体系新型物态及其相关应用价值。不同于静态系统的量子相变由其基态能谱所决定，作为非平衡系统的周期性驱动系统的量子相变由其Floquet准能谱特性所决定。我们将利用Floquet理论研究：1)驱动耗散二能级系统的量子相变及其在退相干抑制中的应用；2)驱动Dicke模型的量子相变及其对超辐射"不可发生"定理的违背；3)驱动一维Kitaev和二位Haldane格点量子系统的新型拓扑量子相变及其对Majorana费米子与分数量子霍尔效应特点的模拟。通过这些研究，我们旨在揭示周期性驱动这一有效的量子调控方案在不断发展的量子工程技术中的应用前景。

随着量子工程的不断发展，如何更加有效地调控单量子态已成为目前量子物理研究的一个前沿问题。在本项目中，我们研究了利用周期性驱动的手段对开放量子系统退相干、对氮空位色心纠缠制备、对光学波导管中的导波动力学和对格点系统中的拓扑相变进行调控；探索该调控对系统量子相变和非平衡动力学的影响；揭发周期性驱动所诱发的体系新型物态及其相关应用价值。不同于静态系统的量子相变由其基态能谱所决定，作为非平衡系统的周期性驱动系统的量子相变由其Floquet准能谱特性所决定。我们围绕周期驱动和开放量子系统建立了束缚态对其非平衡动力学深刻影响的统一物理框架：在周期性驱动系统中发现了由准能谱中Floquet束缚态形成所刻画的新型量子相变和拓扑相变，以此提出了利用周期性驱动抑制退相干、实现光学传播动力学局域化、产生远距离氮空位色心稳定纠缠以及人工合成以Haldane模型大陈数拓扑绝缘相为代表的极端拓扑物态的新颖方案；在开放系统中发现了系统-环境能谱中束缚态形成在退相干抑制、噪声条件下量子计量超高精度恢复和量子速度极限等中的支配作用。受本项目资助，在Physical Review系列杂志等发表SCI论文15篇。我们围绕周期性驱动所取得的以上一系列成果极大地丰富了量子态调控的手段并开辟了人工合成量子极端物态的新手段。