Li Xiaopeng, Sarma S Das
Department of Physics, Condensed Matter Theory Center and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742-4111, USA.
Nat Commun. 2015 May 14;6:7137. doi: 10.1038/ncomms8137.
Versatile controllability of interactions in ultracold atomic and molecular gases has now reached an era where quantum correlations and unconventional many-body phases can be studied with no corresponding analogues in solid-state systems. Recent experiments in Rydberg atomic gases have achieved exquisite control over non-local interactions, allowing novel quantum phases unreachable with the usual local interactions in atomic systems. Here we study Rydberg-dressed atomic fermions in a three-dimensional optical lattice predicting the existence of hitherto unheard-of exotic mixed topological density wave phases. By varying the spatial range of the non-local interaction, we find various chiral density waves with spontaneous time-reversal symmetry breaking, whose quasiparticles form three-dimensional quantum Hall and Weyl semimetal states. Remarkably, certain density waves even exhibit mixed topologies beyond the existing topological classification. Our results suggest gapless fermionic states could exhibit far richer topology than previously expected.
超冷原子和分子气体中相互作用的通用可控性现已进入一个时代，在此时代中，可以研究量子关联和非常规多体相，而固态系统中没有相应的类似物。近期在里德堡原子气体中的实验已实现对非局域相互作用的精确控制，使得原子系统中通常的局域相互作用无法达到的新型量子相成为可能。在此，我们研究三维光学晶格中经里德堡修饰的原子费米子，预测存在迄今闻所未闻的奇异混合拓扑密度波相。通过改变非局域相互作用的空间范围，我们发现了各种具有自发时间反演对称性破缺的手性密度波，其准粒子形成三维量子霍尔和外尔半金属态。值得注意的是，某些密度波甚至展现出超越现有拓扑分类的混合拓扑。我们的结果表明，无隙费米子态可能展现出比先前预期丰富得多的拓扑结构。
