Sbroscia Matteo, Viebahn Konrad, Carter Edward, Yu Jr-Chiun, Gaunt Alexander, Schneider Ulrich
Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland.
Phys Rev Lett. 2020 Nov 13;125(20):200604. doi: 10.1103/PhysRevLett.125.200604.
Quasicrystals are long-range ordered but not periodic, representing an interesting middle ground between order and disorder. We experimentally and numerically study the localization transition in the ground state of noninteracting and weakly interacting bosons in an eightfold symmetric quasicrystalline optical lattice. In contrast to typically used real space in situ techniques, we probe the system in momentum space by recording matter wave diffraction patterns. Shallow lattices lead to extended states whereas we observe a localization transition at a critical lattice depth of V_{0}≈1.78(2)E_{rec} for the noninteracting system. Our measurements and Gross-Pitaevskii simulations demonstrate that in interacting systems the transition is shifted to deeper lattices, as expected from superfluid order counteracting localization. Quasiperiodic potentials, lacking conventional rare regions, provide the ideal testing ground to realize many-body localization in 2D.
准晶体具有长程有序但非周期性，代表了有序与无序之间一个有趣的中间状态。我们通过实验和数值方法研究了八重对称准晶光学晶格中无相互作用和弱相互作用玻色子基态的局域化转变。与通常使用的实空间原位技术不同，我们通过记录物质波衍射图案在动量空间中探测系统。浅晶格导致扩展态，而对于无相互作用系统，我们在临界晶格深度(V_{0}≈1.78(2)E_{rec})处观察到局域化转变。我们的测量和格罗斯 - 皮塔耶夫斯基模拟表明，在相互作用系统中，正如超流序对抗局域化所预期的那样，转变向更深的晶格移动。缺乏传统稀有区域的准周期势提供了在二维中实现多体局域化的理想测试平台。
