We show generalized Galileons — a particular subclass of Horndeski gravity — arise from a consistent Kaluza-Klein reduction of the low-energy effective action of heterotic string theory to first order in α'. This suggests Horndeski theories of gravity have a string-theoretic origin. The form of the Galileonic terms is precisely fixed by parameters of the embedding spacetime, so that only a specific subset of Horndeski theories is permitted by string theory. A novel limit of the model is considered by performing a dimensionfulrescalingofα'.

中文翻译：

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伽利略的起源及其新颖的极限

我们展示了广义伽利略（Horndeski 引力的一个特殊子类），源自于一致的 Kaluza-Klein 将杂质弦理论的低能有效作用简化为 α' 中的一阶。这表明霍恩德斯基的引力理论起源于弦论。伽利略项的形式由嵌入时空的参数精确固定，因此弦理论只允许霍恩德斯基理论的特定子集。通过对α'进行维度重新缩放来考虑模型的新限制。