超越连续极限的狄拉克涡旋模式
Dirac-vortex modes beyond the continuum limit
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中文总结 AI 辅助
研究了凯库勒调制晶格中狄拉克涡旋模式，发现连续模型在离散晶格中失效，初始相位变得可观测且影响模式中心。通过引入微扰将相位相关中心运动转换为光谱响应实现频率调谐，揭示其对初始相位敏感性及在可重构光子器件中的潜力。
中文摘要 AI 辅助
在凯库勒调制晶格中的狄拉克涡旋模式（DVMs）提供了一种波限制的拓扑途径，通常由连续的杰基夫 - 罗西模型描述，其中初始相位作为冗余规范自由度，不影响模式的可观测量。本文表明，当诱导DVMs的复质量纹理不再满足缓变包络近似时，这种情况在离散晶格中会失效。在这种情况下，晶格离散性使初始相位成为一个可物理观测的参数，它会移动DVM中心。通过进一步引入亚晶格反对称微扰，我们将这种与相位相关的中心运动转换为DVM的连续光谱响应，使其频率能在几乎整个拓扑带隙内调谐。我们的模拟和实验结果与考虑模式中心运动的修正连续模型吻合良好。在这个微扰框架内，模型表明频率偏移对初始相位呈现正弦状依赖。这些发现揭示了晶格中实现的DVMs对初始相位的敏感性，这是理想连续杰基夫 - 罗西模型中不存在的重要基本特征，并证明了初始相位工程是通往可重构光子器件的潜在途径。
英文摘要
Dirac-vortex modes (DVMs) in Kekule-modulated lattices provide a topological route to wave confinement and are commonly described by the continuum Jackiw-Rossi model, in which the initial phase acts as a redundant gauge degree of freedom and does not affect observables of the mode. Here we show that this picture breaks down in discrete lattices when the complex mass texture that induces the DVMs no longer satisfies the slowly varying envelope approximation. In this regime, lattice discreteness turns the initial phase into a physically observable parameter that shifts the DVM center. By further introducing a sublattice-antisymmetric perturbation, we convert this phase-dependent center motion into a continuous spectral response of the DVM, enabling its frequency tuning across nearly the entire topological bandgap. Our simulation and experimental results agree well with a revised continuum model accounting for the mode-center motion. Within this perturbative framework, the model shows that the frequency shift exhibits a sinusoidal-like dependence on the initial phase. These findings reveal initial phase-sensitivity of the DVMs realized in lattices, an important and basic feature absent from the ideal continuum Jackiw-Rossi model, and demonstrate initial phase engineering as a potential pathway towards reconfigurable photonic devices.
