Ji Wentao, Zhang Lin, Wang Mengqi, Zhang Long, Guo Yuhang, Chai Zihua, Rong Xing, Shi Fazhan, Liu Xiong-Jun, Wang Ya, Du Jiangfeng
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China.
CAS Key Laboratory of Microscale Magnetic Resonance, University of Science and Technology of China, Hefei 230026, China.
Phys Rev Lett. 2020 Jul 10;125(2):020504. doi: 10.1103/PhysRevLett.125.020504.
Quantum simulation, as a state-of-the-art technique, provides a powerful way to explore topological quantum phases beyond natural limits. Nevertheless, it is usually hard to simulate both the bulk and surface topological physics at the same time to reveal their correspondence. Here we build up a quantum simulator using nitrogen-vacancy center to investigate a three-dimensional (3D) chiral topological insulator, and demonstrate the study of both the bulk and surface topological physics by quantum quenches. First, a dynamical bulk-surface correspondence in momentum space is observed, showing that the bulk topology of the 3D phase uniquely corresponds to the nontrivial quench dynamics emerging on 2D momentum hypersurfaces called band inversion surfaces (BISs). This is the momentum-space counterpart of the bulk-boundary correspondence in real space. Further, the symmetry protection of the 3D chiral phase is uncovered by measuring dynamical spin textures on BISs, which exhibit perfect (broken) topology when the chiral symmetry is preserved (broken). Finally, we measure the topological charges to characterize directly the bulk topology and identify an emergent dynamical topological transition when varying the quenches from deep to shallow regimes. This work demonstrates how a full study of topological phases can be achieved in quantum simulators.
量子模拟作为一种先进技术,为探索超越自然极限的拓扑量子相提供了一种强大的方法。然而,通常很难同时模拟体拓扑物理和表面拓扑物理以揭示它们之间的对应关系。在此,我们利用氮空位中心构建了一个量子模拟器来研究三维(3D)手性拓扑绝缘体,并通过量子猝灭展示了对体拓扑物理和表面拓扑物理的研究。首先,在动量空间中观察到一种动态的体-表面对应关系,表明三维相的体拓扑唯一地对应于在称为能带反转面(BIS)的二维动量超曲面上出现的非平凡猝灭动力学。这是实空间中体-边界对应关系在动量空间中的对应物。此外,通过测量BIS上的动态自旋纹理揭示了三维手性相的对称性保护,当手性对称性被保留(破坏)时,这些纹理表现出完美(破缺)的拓扑结构。最后,我们测量拓扑电荷以直接表征体拓扑,并识别出当将猝灭从深区域变化到浅区域时出现的动态拓扑转变。这项工作展示了如何在量子模拟器中实现对拓扑相的全面研究。