论文标题
相互作用引起的光子对拓扑状态
Interaction-induced topological states of photon pairs
论文作者
论文摘要
迄今为止，拓扑顺序的概念在很大程度上依赖于单粒子带的特性。直到最近，人们已经意识到，相互作用可以对拓扑特性产生巨大影响，这不仅修改了频段的拓扑，而且还可以在原本琐碎的系统中创建拓扑顺序。我们采用了Bose-Hubbard模型的扩展版本，我们研究了一个系统，该系统在单粒子制度中拓扑琐碎，在拓扑上是非平凡的边缘和界面绑定的光子对的界面状态。尽管该模型中光子的结合是由标准的局部相互作用项捕获的，但额外的直接两光子跳跃使系统在拓扑上是非平凡的。除了它们相互作用引起的起源外，预测的两个光子边缘状态还具有一系列出乎意料的特征，包括相应散装带崩溃的稳健性，以及与在连续体中形成界面状态的两光子散射状态的连续性共存的能力。为绑定光子对进行Zak相的严格计算，我们证明了两光子边缘状态的拓扑起源。
To date, the concept of topological order relies heavily on the properties of single-particle bands. Only recently it has been realized that interactions can have a dramatic impact on topological properties not only modifying the topology of the bands but also creating a topological order in an otherwise trivial system. Applying an extended version of the Bose-Hubbard model, we investigate a system which, being topologically trivial in the single-particle regime, harbors topologically nontrivial edge and interface states of repulsively bound photon pairs. Whereas binding of the photons in this model is captured by a standard local interaction term, an additional direct two-photon hopping renders the system topologically non-trivial. Besides their interaction-induced origin, predicted two-photon edge states exhibit a range of other unexpected features, including the robustness to collapse of the corresponding bulk band and the ability to coexist with the continuum of two-photon scattering states forming a bound state in the continuum. Performing rigorous calculation of the Zak phase for bound photon pairs, we prove the topological origin of the two-photon edge states.
