论文标题
平面系统中两个玻色子的相互作用引起的拓扑特性
Interaction-induced topological properties of two bosons in flat-band systems
论文作者
论文摘要
在平坦系统中，破坏性干扰导致非相互作用颗粒的定位，并禁止其通过晶格运动。但是，在存在相互作用的情况下，相邻的单粒子局部特征状态之间的重叠可能使粒子的结合对传播。在这项工作中，我们展示了如何调整这些相互作用诱导的跳动以获得各种两体拓扑状态。特别是，我们考虑了两个装入钻石链晶格的轨道角动量$ L = 1 $状态的相互作用的玻色子，其中有效的$π$通量可能会产生完全平坦的单粒子能量景观。在弱相互互动的极限中，我们为两玻色子准粒子提供了有效的单粒子模型，这些模型提供了拓扑状态如何出现的直观图片。通过精确的对角度计算，我们对这些状态进行基准测试，并证明它们也存在于强烈的相互作用并远离严格的平坦限制。此外，我们确定了一组双重局部的两波孔扁平带状态，这些状态引起了用于任意相互作用的Aharonov-bohm笼子的特殊实例。
In flat-band systems, destructive interference leads to the localization of non-interacting particles and forbids their motion through the lattice. However, in the presence of interactions the overlap between neighbouring single-particle localized eigenstates may enable the propagation of bound pairs of particles. In this work, we show how these interaction-induced hoppings can be tuned to obtain a variety of two-body topological states. In particular, we consider two interacting bosons loaded into the orbital angular momentum $l=1$ states of a diamond-chain lattice, wherein an effective $π$ flux may yield a completely flat single-particle energy landscape. In the weakly-interacting limit, we derive effective single-particle models for the two-boson quasiparticles which provide an intuitive picture of how the topological states arise. By means of exact diagonalization calculations, we benchmark these states and we show that they are also present for strong interactions and away from the strict flat-band limit. Furthermore, we identify a set of doubly localized two-boson flat-band states that give rise to a special instance of Aharonov-Bohm cages for arbitrary interactions.
