AI 中文总结
研究通过微观理论推导格林函数，评估珀塞尔因子等，探讨二维电子气中朗道能级非局域性。朗道能级响应的空间色散产生非局域效应，改变数百纳米内响应，部分特征与相关实验一致。
AI 中文摘要
在二维电子气中，强垂直磁场将电子限制在量子化的回旋轨道上，产生具有离散轨道半径的朗道能级。即使由磁长度设定的最小朗道轨道，在几特斯拉的磁场下也跨越数十纳米，对电磁激发产生固有的非局域响应。我们从非局域磁化率的微观理论推导出格林函数，评估了珀塞尔因子、兰姆位移和来自近端偶极发射器的发射光谱。朗道能级响应的空间色散导致的显著非局域效应改变了数百纳米距离内实验相关情况的响应，特别是由于回旋频率倍数处的近场梯度使局部偶极禁戒跃迁变亮。相关长度尺度是当前纳米结构太赫兹架构的典型尺度，我们的一些非局域特征与最近使用朗道能级极化激元的实验一致。
英文摘要
In a two-dimensional electron gas, a strong perpendicular magnetic field confines electrons to quantized cyclotron orbits, giving rise to Landau levels with discrete orbit radii. Even the smallest Landau orbit, set by the magnetic length, spans tens of nanometers for fields of a few Tesla, imposing an intrinsic nonlocal response to electromagnetic excitations. From a microscopic theory of the nonlocal susceptibility, we derive the Green's function, the central quantity governing all electromagnetic interactions, and evaluate Purcell factors, Lamb shifts, and emission spectra from a proximal dipole emitter beyond the Markov and rotating-wave approximations. Significant nonlocal effects resulting from spatial dispersion of the Landau level response modify the response for experimentally relevant situations up to distances of hundreds of nanometers and, in particular, brighten locally dipole-forbidden transitions due to near-field gradients at multiples of the cyclotron frequency. The relevant length scales are typical of state-of-the-art nanostructured terahertz architectures, and some of our nonlocal features are consistent with recent experiments using Landau level polaritons.
