冷原子体系在周期驱动下的动力学研究

随着实验上调控技术的发展和成熟，研究周期驱动量子体系逐渐成为量子调控前沿领域中一个重要的课题。基于冷原子等体系开展周期驱动动力学研究可以充分发挥此类系统易于调控的特征，丰富并深化人们对周期驱动动力学的理解和认识。本项目通过Floquet理论、对称性分析、Jordan-Wigner变换、Schwinger-boson变换等方法，拟从三方面研究周期驱动动力学的性质。具体而言：(1) 通过研究玻色-爱因斯坦凝聚体和NV体系在连续周期驱动下的退相干过程，探索连续周期驱动在动力学解耦方面的有效性；(2) 通过研究两分量玻色-爱因斯坦凝聚体在离散脉冲周期驱动下的动力学，验证冷原子体系中的离散时间晶体；(3) 通过研究一维海森堡自旋链在离散脉冲周期驱动下的动力学，揭示拓扑保护的离散时间晶体特征，并最终对目前存在的相关实验从理论上做出统一的解释。

With the development and maturity of experimental control, studying periodically driven quantum systems has become a major research topic in the frontier of quantum control. Thanks to their high controllability, cold atomic and other systems have enriched and deepened people’s understanding of periodic driving. Based on the methods, including Floquet theory, symmetry analysis, Jordan-Wigner transformation, Schwinger-boson transformation, etc., this project takes three typical aspects to study properties of periodically driving dynamics. To be specific, (1) by studying the process of decoherence for the Bose-Einstein condensate and NV center under continuously periodic driving, a new method of dynamical decoupling is proposed; (2) by studying periodically driving two-component Bose-Einstein condensate, the discrete time crystal in ultracold atoms is demonstrated; (3) by studying periodically driving one dimensional Heisenberg spin chain, the topologically protected discrete time crystal is classified and finally we aim at explaining the existed experiments about discrete time crystal.