Time: 10:00am (UTC/GMT+8:00, Beijing/Shanghai), Apr. 21 (Wedn.), 2021

Venue: KITS Meeting Room, 4th floor, No. 7 Building, UCAS [View Map]

Speaker: Qian-Qian CHEN (HUST)

Abstract:
With the development of topological physics, the search for topological structures has not been limited to condensed matter systems. Synthetic quantum systems, such as ultracold atomic gases and nitrogen-vacancy centers in diamond, with less influence from impurities, are much more controllable, enabling the realization and observation of many novel topological phenomena. In synthetic quantum systems, dynamical modulation is one of the most common methods used to simulate topological structures and phenomena. Compared to steady-state systems, dynamical systems have many unique topological properties, such as those protected by symmetries in the time dimension. However, in dynamical systems, decoherence can deteriorate the experimentally observed topological phenomena. In this presentation, I will mainly focus on topological phenomena protected by symmetries in the time dimension, and also present a dynamical decoupling scheme to suppress noise in systems under a two-tone drive so as to facilitate the observation of topological phase transition.

摘要：

随着拓扑物理学的发展，人们不仅仅局限于在凝聚态系统中寻找各种拓扑结构，也开始在其它量子多体系统，特别是各种人工量子系统中开展与拓扑物理学相关的研究，这类多体系统包括超冷原子气体和金刚石中的氮-空位色心等。相较于传统的固态系统，这些人工量子系统拥有更高的可操控性，杂质等因素对系统的影响也更小，从而能实现并观测到许多固体中所难以实现的新奇现象。在人工量子系统中，外加动力学调制是用来实现对拓扑结构以及拓扑现象的模拟的最常用方法之一。相较于定态系统，动力学系统有很多独特的拓扑性质，比如由时间维度上的对称性所保护的拓扑性质。其次，在动力学系统中，系统中的退相干会对实验观测到的拓扑现象产生一定的不良影响。在这个报告中，我将主要介绍以下两方面的内容，即由时间维度上的对称性所保护的拓扑现象，以及在外加两个频率驱动的系统中抑制噪声、从而更有效地观测拓扑相变信号的动态去耦方案。

Invited by Prof. Zheng Zhu