Detecting Fractional Chern Insulators in Optical Lattices through Quantized Displacement.
Detecting Fractional Chern Insulators in Optical Lattices through Quantized Displacement.
复制标题
DOI：
10.1103/physrevlett.125.236401
复制
发表时间：
2020-03
影响因子：
8.6
通讯作者：
J. Motruk;Ilyoun Na
中科院分区：
文献类型：
--
作者：
J. Motruk;Ilyoun Na
在冷原子系统中实现物质的相互作用拓扑态，如分数陈绝缘体(FCIS)，最近已经达到了实验范围，这是因为利用合成规范场的光学晶格工程提供了所需的拓扑带结构。然而，检测它们的存在可能会被证明是困难的，因为类似于固态系统中的输运测量在冷原子装置中执行是具有挑战性的，并且必须找到替代方案。结果表明，对于在简谐囚禁势约束下的相互作用玻色子的Harper-Hofstadter模型的最低能带实现的ν=1/2FCi态，分数量子化的霍尔电导σ_(Xy)可以由原子云在恒定力作用下的位移精确地确定，这为探测态的拓扑性质提供了合适的实验测量信号。利用矩阵积态算法，我们证明了在圆柱体和正方形几何结构中，在一定场强范围内，在禁闭势顶的恒定力场作用下，粒子云在时间上的运动与σ_(Xy)成正比。
The realization of interacting topological states of matter such as fractional Chern insulators (FCIs) in cold atom systems has recently come within experimental reach due to the engineering of optical lattices with synthetic gauge fields providing the required topological band structures. However, detecting their occurrence might prove difficult since transport measurements akin to those in solid state systems are challenging to perform in cold atom setups and alternatives have to be found. We show that for a ν=1/2 FCI state realized in the lowest band of a Harper-Hofstadter model of interacting bosons confined by a harmonic trapping potential, the fractionally quantized Hall conductivity σ_{xy} can be accurately determined by the displacement of the atomic cloud under the action of a constant force which provides a suitable experimentally measurable signal for detecting the topological nature of the state. Using matrix-product state algorithms, we show that, in both cylinder and square geometries, the movement of the particle cloud in time under the application of a constant force field on top of the confining potential is proportional to σ_{xy} for an extended range of field strengths.