论文标题
两个量子指南针模型的故事
A Tale of Two Quantum Compass Models
论文作者
论文摘要
我们研究了量子指南针模型(QCM)的两个变体。首先显示出纯蜂窝QCM QCM,显示出与早期的研究,在$ 3D $的普遍性类别中从$ xx $ - $ zz $订购的阶段进行量子相变(QPT)。在分数化的Parton结构中,这描述了高阶拓扑超级流体和感谢您的``超级氟化物绝缘子''的``超流体绝缘子'',后者被描述为Partons的$ p $ - 波谐振价债券。第二种变体是平方晶格上的无旋转费米QCM,在每个原子上具有高角度动量状态的冷原子晶格中很感兴趣。我们使用互补方法探索了巡回和局部限制中有限的轨道秩序转变。在巡回限制中,我们通过一个不连贯的类似于中间$ t $的不连贯的不良金属状状态,从$ 2D $ $ t $ $ t $ t $低于$ t $ the of the或berbialborebility oferbialbore,我们发现了一个不合时宜的差异状态($ t $ t $,$ 2D $ symptry-broken的绝缘子,在低于$ $ t $下方,我们均在低于$ the或berb的标准。最后,我们讨论了这两种变体中的特定于工程,可调和现实的扰动,可以作为一个操场,用于模拟拓扑排序和琐碎阶段之间的各种异国情调的QPT。在冷原子的情况下,我们提出了一种新颖的方法,以在Bose超氟和电荷密度波绝缘体之间的QPT处设计出异国情调的激发胶液相。我们认为,约瑟夫森交界阵列的设计和操纵冷原子晶格的进步提供了模拟在可预见的未来进行此类新型物质的希望。
We investigate two variants of quantum compass models (QCMs). The first, an orbital-only honeycomb QCM, is shown to exhibit a quantum phase transition (QPT) from a $XX$- to $ZZ$-ordered phase in the $3d$-Ising universality class, in accord with earlier studies. In a fractionalized parton construction, this describes a ``superfluid-Mott insulator'' transition between a higher-order topological superfluid and the toric code, the latter described as a $p$-wave resonating valence bond state of the partons. The second variant, the spinless fermion QCM on a square lattice, is of interest in the context of cold-atom lattices with higher-angular momentum states on each atom. We explore finite-temperature orbital order-disorder transitions in the itinerant and localized limits using complementary methods. In the itinerant limit, we uncover an intricate temperature ($T$)-dependent dimensional crossover from a high-$T$ quasi-$1d$ insulator-like state, via an incoherent bad-metal-like state at intermediate $T$, to a $2d$ symmetry-broken insulator at low $T$, well below the ``orbital'' ordering scale. Finally, we discuss how engineering specific, tunable, and realistic perturbations in both these variants can act as a playground for simulating a variety of exotic QPTs between topologically ordered and trivial phases. In the cold-atom context, we propose a novel way to engineer a possible realisation of the exotic exciton Bose liquid phase at a QPT between a Bose superfluid and a charge density wave insulator. We argue that advances in the design of Josephson junction arrays and manipulating cold-atom lattices offer the hope of simulating such novel phases of matter in the foreseeable future.