Normal modes are intimately related to the quadratic approximation of a potential at its hyperbolic equilibria. Here we extend the notion to the case where the Taylor expansion for the potential at a critical point starts with higher order terms, and show that such an extension shares some of the properties of standard normal modes. Some symmetric examples are considered in detail.

中文翻译：

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高阶普通模式

正常模式与双曲平衡下的电势的二次逼近密切相关。在这里，我们将概念扩展到临界点处的泰勒展开式以高阶项开始的情况，并表明这种扩展式具有标准法向模态的某些属性。详细考虑一些对称示例。