Disformal invariance of second order scalar-tensor theories: Framing the Horndeski action
Disformal invariance of second order scalar-tensor theories: Framing the Horndeski action
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DOI：
10.1103/physrevd.88.084020
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发表时间：
2013-06
影响因子：
5
通讯作者：
D. Bettoni;S. Liberati
中科院分区：
文献类型：
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作者：
D. Bettoni;S. Liberati
Horndeski作用量是最普遍的一个涉及度量和标量场，导致在四维二阶场方程。作为著名的标量-张量理论的自然推广，它的结构和性质值得沿着在后一种背景下积累的经验加以分析。在这里，我们认为，非正式的转换，Horndeski理论，一个类似的作用，共形变换的标量张量理论的一个l`a布朗-迪克。我们确定了最一般的变换保持二阶场方程，并讨论了这类理论的可行框架的问题，特别是在所谓的爱因斯坦框架中的可能性。最后，我们研究了这些框架的物理等价性及其相互关系。
The Horndeski action is the most general one involving a metric and a scalar field that leads to second order field equations in four dimensions. Being the natural extension of the well known Scalar-Tensor theories, its structure and properties are worth analysing along the experience accumulated in the latter context. Here we argue that disformal transformations play, for the Horndeski theory, a similar role to that of conformal transformations for Scalar-Tensor theories a l`a Brans-Dicke. We identify the most general transformation preserving second order field equations and discuss the issue of viable frames for this kind of theories, in particular the possibility to cast the action in the so called Einstein frame. Finally, we investigate the physical equivalence of such frames and their reciprocal relationship.