Unconventional Weyl points with topological charges higher than 1 can transform into various complex unconventional Weyl exceptional contours under non-Hermitian perturbations. However, theoretical studies of these exceptional contours have been limited to tight-binding models. Here, we propose to realize unconventional Weyl exceptional contours in photonic continua—non-Hermitian anisotropic chiral plasma, based on ab initio calculation by Maxwell’s equations. By perturbing in-plane permittivity, an unconventional Weyl point can transform into a quadratic Weyl exceptional ring, a type I Weyl exceptional chain with one chain point, a type II Weyl exceptional chain with two chain points, or other forms. Realistic metamaterials with effective constitutive parameters are proposed to implement these unconventional Weyl exceptional contours. Our work paves a way toward exploration of exotic physics of unconventional Weyl exceptional contours in non-Hermitian topological photonic continua.

中文翻译：

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非厄米光子连续体中的非常规外尔异常轮廓

拓扑荷大于1的非常规外尔点可以在非厄米微扰下转化为各种复杂的非常规外尔异常等高线。然而，对这些异常轮廓的理论研究仅限于紧束缚模型。在这里，我们建议在光子连续体——非厄米各向异性手性等离子体中实现非常规外尔异常轮廓，基于ab initio麦克斯韦方程计算。通过扰动面内介电常数，非常规外尔点可以转变为二次外尔异常环、具有一个链点的I型外尔异常链、具有两个链点的II型外尔异常链或其他形式。提出了具有有效本构参数的逼真超材料来实现这些非常规的 Weyl 异常轮廓。我们的工作为探索非厄米拓扑光子连续体中非常规外尔异常轮廓的奇异物理学铺平了道路。