论文标题

相关的脆弱拓扑:Parton方法

Correlated Fragile Topology: a Parton Approach

论文作者

Latimer, Katherine, Wang, Chong

论文摘要

易碎的拓扑绝缘子(FTI)可以看作是一种几乎原子的绝缘子,即使基本的晶格希尔伯特空间仅包含带电的状态,但仍在某些真实空间点上定位的紧急负电荷。使用现代拓扑带理论对自由费米恩系统中的脆弱拓扑结构进行了良好的研究。但是,即使对于密切相关的系统,该概念也得到了很好的定义,并且在自由费米昂理论中无法实现的脆弱状态存在。在这项工作中,我们为这种支持相关的FTI提出了相当普遍的Parton构建。在我们的Parton构造中,相关的量规对称性完全是希格斯的,仅导致短程纠缠状态。随着带负电荷的Parton的残留物,FTI的有效负电荷自然出现。对于带有$ SU(2)$旋转对称性的稀释电子,脆弱的相位可以看作是电荷的FTI- $ 2 $,Spin Singlet Singlet Bosonic Cooper Pairs。我们讨论了有关无旋转和刺费的相关FTI的一些示例,包括先前在文献中讨论过的蜂窝晶格上的一些“无特征Mott绝缘子”。

A fragile topological insulator (FTI) can be viewed as an almost-atomic insulator, with emergent negative charges localized at certain real space points, even though the underlying lattice Hilbert space contains only positively charged states. Fragile topology in free fermion systems has been fruitfully studied using modern topological band theory. However, the concept is well defined even for strongly correlated systems, and fragile states that cannot be realized within free fermion band theory exist abundantly. In this work we propose a rather general parton construction for such correlation-enabled FTIs. In our parton construction the associated gauge symmetries are completely Higgsed, resulting in only short-range entangled states. The effective negative charges in the FTIs emerge naturally as the remnants of negatively charged partons. For spinful electrons with $SU(2)$ spin-rotation symmetry, the fragile phases can be viewed as FTIs of charge-$2$, spin singlet bosonic Cooper pairs. We discuss a few examples of correlated FTIs for both spinless and spinful fermions, including some "featureless Mott insulators" on the honeycomb lattice previously discussed in the literature.

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