论文标题
Chern乐队的黑暗状态：设计具有更高Chern号码的平坦乐队
A dark state of Chern bands: Designing flat bands with higher Chern number
论文作者
论文摘要
我们介绍了一个方案，通过该方案，可以通过Bloch频段的连贯操作在超低气体中设计具有更高Chern Number $ \ Vert C \ Vert> 1 $的平面带。受量子访问方法的启发，我们的方法包括通过通过谐振过程耦合一组源频段来创建“深色bloch频段”。考虑到三个频段的$λ$系统，发现黑暗频段的Chern数字遵循一个简单的总和规则，根据源频段的Chern数字：$ C_D \！= \！\！c_1+C_2-C_3 $。总的来说，我们的Dark-State方案实现了一个几乎平坦的Bloch乐队，具有可预测且可调的Chern Number $ C_D $。我们说明了基于$λ$系统的方法，该系统由Harper-Hofstadter模型的频段组成，该模型带来了一个几乎平坦的Chern频段，其带有$ C_D \！= \！2 $。我们探索一个逼真的序列，以将原子加载到深色Chern带中，以及基于Hall漂移测量值的探测方案。深色Chern乐队提供了一个实用的平台，在该平台中，可以在超低气体中实现异国情调的分数量子厅状态。
We introduce a scheme by which flat bands with higher Chern number $\vert C\vert>1$ can be designed in ultracold gases through a coherent manipulation of Bloch bands. Inspired by quantum-optics methods, our approach consists in creating a "dark Bloch band" by coupling a set of source bands through resonant processes. Considering a $Λ$ system of three bands, the Chern number of the dark band is found to follow a simple sum rule in terms of the Chern numbers of the source bands: $C_D\!=\!C_1+C_2-C_3$. Altogether, our dark-state scheme realizes a nearly flat Bloch band with predictable and tunable Chern number $C_D$. We illustrate our method based on a $Λ$ system, formed of the bands of the Harper-Hofstadter model, which leads to a nearly flat Chern band with $C_D\!=\!2$. We explore a realistic sequence to load atoms into the dark Chern band, as well as a probing scheme based on Hall drift measurements. Dark Chern bands offer a practical platform where exotic fractional quantum Hall states could be realized in ultracold gases.
