论文标题
带有Aubry-André-Harper调制的远程Kitaev链的拓扑特性
Topological properties of the long-range Kitaev chain with Aubry-André-Harper modulation
论文作者
论文摘要
我们介绍了具有远程配对项的基塔夫链的拓扑特性,并在存在奥布里·安德烈·亨特的现场潜力的情况下进行了详细研究。具体而言,我们认为代数衰减的超导配对振幅;发现这种衰变的指数确定了临界配对强度,在链条上拓扑保持脚踏实地。在临界配对的上方,在中央间隙中观察到拓扑边缘模式。对于配对的足够快速衰减,这些模式被识别为Majorana零模型。但是,如果配对术语衰减缓慢,则模式变为巨大的狄拉克模式。有趣的是,这些巨大的模式仍表现出零能量的真实水平交叉,这表明与Majorana Physics的初始关系。我们还观察到在远距离系统中明显缺乏散装的对应关系,在该系统中,散装拓扑不变性保持恒定,而在系统边缘的行为中出现了巨大的变化。除了零能量周围的中心差距外,Aubry-André-Harper电位还会导致非零能量下的其他能量差距。至于类似的短距离模型,这些间隙中的边缘模式可以通过2D Chern不变性表征。但是,与短距离模型相反,此拓扑不变不再与边缘模式交叉的数量相对应。这提供了另一个示例,以削弱该模型中发生的散装对应关系。最后,我们讨论了使用超电原子和冷凝物质系统对模型的可能实现。
We present a detailed study of the topological properties of the Kitaev chain with long-range pairing terms and in the presence of an Aubry-André-Harper on-site potential. Specifically, we consider algebraically decaying superconducting pairing amplitudes; the exponent of this decay is found to determine a critical pairing strength, below which the chain remains topologically trivial. Above the critical pairing, topological edge modes are observed in the central gap. For sufficiently fast decay of the pairing, these modes are identified as Majorana zero-modes. However, if the pairing term decays slowly, the modes become massive Dirac modes. Interestingly, these massive modes still exhibit a true level crossing at zero energy, which points towards an initimate relation to Majorana physics. We also observe a clear lack of bulk-boundary correspondence in the long-range system, where bulk topological invariants remain constant, while dramatic changes appear in the behavior at the edge of the system. In addition to the central gap around zero energy, the Aubry-André-Harper potential also leads to other energy gaps at non-zero energy. As for the analogous short-range model, the edge modes in these gaps can be characterized through a 2D Chern invariant. However, in contrast to the short-range model, this topological invariant does not correspond to the number of edge mode crossings anymore. This provides another example for the weakening of the bulk-boundary correspondence occurring in this model. Finally, we discuss possible realizations of the model with ultracold atoms and condensed matter systems.