Observation of Symmetry-Protected Selection Rules in Periodically Driven Quantum Systems
Observation of Symmetry-Protected Selection Rules in Periodically Driven Quantum Systems
复制标题
周期性驱动量子系统中对称保护选择规则的观察
DOI：
10.1103/physrevlett.127.140604
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发表时间：
2021
影响因子：
8.6
通讯作者：
Cappellaro, Paola
中科院分区：
文献类型：
--
作者：
Wang, Guoqing;Li, Changhao;Cappellaro, Paola
周期驱动（Floquet）量子系统由于其丰富的动力学特性，近年来成为非平衡物理研究的热点。时间周期系统不仅表现出类似于空间周期系统的对称性，而且还表现出对称性破缺所带来的新的行为。这种动力学对称性的表征是至关重要的，但往往具有挑战性，由于有限的驱动强度和缺乏实验可访问的表征技术。在这里，我们将展示如何揭示动力学对称性，即奇偶性，旋转，和粒子-空穴对称性，通过观察由量子力学引起的Floquet选择规则。值得注意的是，我们利用调制驱动，以达到强的光-物质耦合制度，我们引入了一个协议，实验提取Floquet状态之间的过渡矩阵元素从系统的相干演化。利用金刚石中的氮空位中心作为实验平台，我们执行我们的方案，观察了金刚石中的氮空位保护暗态和暗带，以及隧穿的相干破坏。我们的工作展示了如何利用量子控制工具包来研究强驱动Floquet系统的拓扑阶段中出现的动力学对称性。
Periodically driven (Floquet) quantum systems have recently been a focus of nonequilibrium physics by virtue of their rich dynamics. Time-periodic systems not only exhibit symmetries that resemble those in spatially periodic systems, but also display novel behavior that arises from symmetry breaking. Characterization of such dynamical symmetries is crucial, but often challenging due to limited driving strength and lack of an experimentally accessible characterization technique. Here, we show how to reveal dynamical symmetries, namely, parity, rotation, and particle-hole symmetries, by observing symmetry-induced Floquet selection rules. Notably, we exploit modulated driving to reach the strong light-matter coupling regime, and we introduce a protocol to experimentally extract the transition matrix elements between Floquet states from the system coherent evolution. By using nitrogen-vacancy centers in diamond as an experimental test bed, we execute our protocol to observe symmetry-protected dark states and dark bands, and coherent destruction of tunneling. Our work shows how one can exploit the quantum control toolkit to study dynamical symmetries that arise in the topological phases of strongly driven Floquet systems.