AI 中文总结
研究具有准周期调制跃迁振幅的一维非厄米六边形Harper模型，揭示其金属、多重分形、绝缘相的不同输运特征，表明多重分形相是输运的关键介导者。
AI 中文摘要
我们研究了具有准周期调制跃迁振幅的一维非厄米六边形Harper模型。在厄米极限下，该模型呈现金属相、绝缘相和多重分形相，各相具有不同的本征态特性。引入非厄米性后，相图发生质的改变：金属区域扩展，且非厄米皮肤效应产生强边界敏感性。通过分析波包动力学，我们揭示了金属、多重分形和绝缘区域中质的不同输运特征：金属区域中，非互易跃迁诱导有限滑动，产生厄米模型不存在的弹道质心运动，同时波包扩散被抑制并呈现扩散标度；多重分形区域作为独特的动力学相，支持增强的扩散和有限滑动，两者均主要为超扩散性质，与金属区域滑动（扩散）呈现弹道（扩散）标度形成鲜明对比，且这些特征与厄米对应物显著不同；绝缘区域中，扩散和滑动均被强烈抑制。我们通过研究单粒子纠缠熵的不同增长轮廓，再次证实了这些有趣的输运特性，其中波包扩散的效应清晰显现。这些结果表明，跃迁振幅的准周期性与非厄米性相结合，使多重分形相成为输运的关键介导者。
英文摘要
We investigate a one-dimensional non-Hermitian hexagonal Harper model with quasiperiodically modulated hopping amplitudes. In the Hermitian limit, the model exhibits metallic, insulating, and multifractal phases characterized by distinct eigenstate properties. Upon introducing non- Hermiticity, the phase diagram is qualitatively altered, with an expansion of metallic regions and strong boundary sensitivity arising from the non-Hermitian skin effect. By analyzing wave-packet dynamics, we uncover qualitatively distinct transport signatures in metallic, multifractal, and in- sulating regimes. In the metallic region, nonreciprocal hopping induces finite sliding, resulting in ballistic center-of-mass motion that is absent in the Hermitian model, while wave-packet spreading is simultaneously suppressed and exhibits diffusive scaling. Interestingly, the multifractal regime emerges as a distinct dynamical phase supporting both enhanced spreading and finite sliding, both primarily of superdiffusive nature, in contrast to metallic regions where sliding (spreading) shows ballistic (diffusive) scaling. These features are markedly different from their Hermitian counterpart. On the other hand, in the insulating region, both the spreading and sliding are strongly suppressed. We reconfirm these intriguing transport characteristics by investigating the distinct growth profile of single-particle entanglement entropy where the effect of spreading of the wave-packet is clearly manifested. These results demonstrate that quasiperiodicity in hopping amplitudes, combined with non-Hermiticity, establishes the multifractal regime as a key mediator of transport.
