具有交错非互易腿间跳跃的梯子中的可调谐非厄米趋肤效应和拓扑相
Tunable non-Hermitian skin effect and topological phases in ladders with staggered nonreciprocal inter-leg hopping
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中文总结 AI 辅助
研究具有交错非互易腿间跳跃的梯子模型的非厄米趋肤效应和拓扑相，通过调整参数实现NHSE方向反转等，证明腿间耦合扩大拓扑非平凡范围，增加非互易性改变相边界，确立此跳跃为设计相关效应和相的有效机制。
中文摘要 AI 辅助
我们研究了具有交错非互易腿间跳跃的梯子模型中的非厄米趋肤效应（NHSE）和拓扑相，该模型由一个Su-Schrieffer-Heeger（SSH）链与一个正常紧束缚链耦合而成。通过调整系统参数，我们表明在开放边界条件下NHSE的方向可以反转，甚至可以变得与能量相关。NHSE在周期边界条件下由谱缠绕数进一步表征。我们进一步证明腿间耦合显著扩大了拓扑非平凡参数范围。值得注意的是，零能量拓扑边缘模式位于梯子的不同腿上，其特征是实空间缠绕数$W = \pm1$。此外，增加腿间跳跃的非互易性会改变拓扑相边界，并最终使系统进入拓扑平凡相。我们的结果确立了交错非互易腿间跳跃作为在梯子系统中设计非厄米趋肤效应和拓扑相的有效机制。
英文摘要
We investigate the non-Hermitian skin effect (NHSE) and topological phases in a ladder model with staggered nonreciprocal inter-leg hopping, consisting of an Su-Schrieffer-Heeger (SSH) chain coupled to a normal tight-binding chain. By tuning the system parameters, we show that the direction of the NHSE under open boundary conditions can be reversed and can even become energy dependent. The NHSE is further characterized by the spectral winding number under periodic boundary conditions. We further demonstrate that the inter-leg coupling significantly enlarges the topologically nontrivial parameter regime. Remarkably, the zero-energy topological edge modes reside on different legs of the ladder and are characterized by real-space winding numbers $W=\pm1$. Furthermore, increasing the nonreciprocity of the inter-leg hopping modifies the topological phase boundaries and eventually drives the system into a topologically trivial phase. Our results establish staggered nonreciprocal inter-leg hopping as an effective mechanism for engineering both the non-Hermitian skin effect and topological phases in ladder systems.
