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arXiv 1606.02677hep-thastro-ph.COgr-qc
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共形对称在引力和标准模型中的作用

The role of conformal symmetry in gravity and the standard model

Stefano Lucat, Tomislav Prokopec

摘要:

在本文中,我们考虑共形对称的背景下,流形的一般仿射联络。我们将度量的保角变换律推广到一般的度量相容仿射联络,发现它是测地线方程和黎曼张量的对称。我们推导出广义Jacobi方程和Raychaudhuri方程,并证明它们都是共形不变的。本文利用测地线偏差~(Jacobi)方程分析了测地线在不同共形标架中的性质。既然我们发现我们的共形对称性在经典纯爱因斯坦引力中是精确的,我们问是否可以把它推广到标准模型。我们发现,对于矢量场、费米子场和标量场,可以写出任意维的共形不变拉格朗日量,但这种拉格朗日量在四维中仅是规范不变的。只要引入一个介子场,引力就可以与物质共形耦合。

英文摘要:

In this paper we consider conformal symmetry in the context of manifolds with general affine connection. We extend the conformal transformation law of the metric to a general metric compatible affine connection, and find that it is a symmetry of both the geodesic equation and the Riemann tensor. We derive the generalised Jacobi equation and Raychaudhuri equation and show that they are both conformally invariant. Using the geodesic deviation~(Jacobi) equation we analyse the behaviour of geodesics in different conformal frames. Since we find that our version of conformal symmetry is exact in classical pure Einstein's gravity, we ask whether one can extend it to the standard model. We find that it is possible to write conformal invariant lagrangians in any dimensions for vector, fermion and scalar fields, but that such lagrangians are only gauge invariant in four dimensions. Provided one introduces a dilaton field, gravity can be conformally coupled to matter.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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