Quantum superposition demonstrated higher-order topological bound states in the continuum

• 作者: Yao Wang Bi-Ye Xie Yong-Heng Lu Yi-Jun Chang Hong-Fei Wang Jun Gao Zhi-Qiang Jiao Zhen Feng Xiao-Yun Xu Feng Mei Suotang Jia Ming-Hui Lu Xian-Min Jin
• 来源期刊: 光：科学与应用（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: Articles
• 页码范围: 1789-1796
• 页数: 8页
• 语种: 英文

摘要

Higher-order topological insulators, as newly found non-trivial materials and structures, possess topological phases beyond the conventional bulk-boundary correspondence. In previous studies, in-gap boundary states such as the corner states were regarded as conclusive evidence for the emergence of higher-order topological insulators. Here, we present an experimental observation of a photonic higher-order topological insulator with corner states embedded into the bulk spectrum, denoted as the higher-order topological bound states in the continuum. Especially, we propose and experimentally demonstrate a new way to identify topological corner states by exciting them separately from the bulk states with photonic quantum superposition states. Our results extend the topological bound states in the continuum into higher-order cases, providing an unprecedented mechanism to achieve robust and localized states in a bulk spectrum. More importantly, our experiments exhibit the advantage of using the time evolution of quantum superposition states to identify topological corner modes, which may shed light on future exploration between quantum dynamics and higher-order topological photonics.