Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Phys Rev Lett. 2019 Mar 22;122(11):110404. doi: 10.1103/PhysRevLett.122.110404.
Quasicrystals are long-range ordered and yet nonperiodic. This interplay results in a wealth of intriguing physical phenomena, such as the inheritance of topological properties from higher dimensions, and the presence of nontrivial structure on all scales. Here, we report on the first experimental demonstration of an eightfold rotationally symmetric optical lattice, realizing a two-dimensional quasicrystalline potential for ultracold atoms. Using matter-wave diffraction we observe the self-similarity of this quasicrystalline structure, in close analogy to the very first discovery of quasicrystals using electron diffraction. The diffraction dynamics on short timescales constitutes a continuous-time quantum walk on a homogeneous four-dimensional tight-binding lattice. These measurements pave the way for quantum simulations in fractal structures and higher dimensions.
准晶具有长程有序但又非周期性的特点。这种相互作用产生了丰富的有趣物理现象，例如拓扑性质从更高维度的继承，以及在所有尺度上存在非平凡的结构。在这里，我们报告了第一个实验证明的八重旋转对称光学晶格，实现了超冷原子的二维准晶势。我们使用物质波衍射观察到这种准晶结构的自相似性，这与使用电子衍射首次发现准晶非常相似。在短时间尺度上的衍射动力学构成了在均匀的四维紧束缚晶格上的连续时间量子漫步。这些测量为分形结构和更高维度的量子模拟铺平了道路。
