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arXiv 0803.2438hep-thgr-qc
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具有消失量子修正的度量

Metrics With Vanishing Quantum Corrections

A. A. Coley, G. W. Gibbons, S. Hervik, C. N. Pope

摘要:

我们研究经典爱因斯坦方程或超引力方程的解,这些方程可以求解任何一组量子修正的爱因斯坦方程,其中爱因斯坦张量加上度量的倍数等于一个对称守恒张量$T_{μν}$,该张量是由涉及度量的收缩和曲率张量的任意协变导数的幂的项的和构造的。一个经典解,如爱因斯坦度量,称为{ \it universal},如果在爱因斯坦度量上计算时,$T_{μν}$是度量的倍数。一个Ricci平坦的经典解称为{ \it强泛解},如果在该Ricci平坦度量上求值时,$T_{μν}$为零。众所周知,四维时空中的pp波是强普适的。我们把注意力集中在一个自然的概括;爱因斯坦度量与holonomy ${\rm Sim} (n-2)$,其中所有的标量不变量为零或常数。在四维空间中,我们证明了广义的加纳-汤普森度量是弱普适的,而戈德堡-克尔度量是强普适的;事实上,我们证明了普适性扩展到所有的四维${\rm Sim}(2)$爱因斯坦度量。我们还讨论了更高维度的推广。

英文摘要:

We investigate solutions of the classical Einstein or supergravity equations that solve any set of quantum corrected Einstein equations in which the Einstein tensor plus a multiple of the metric is equated to a symmetric conserved tensor $T_{μν}$ constructed from sums of terms the involving contractions of the metric and powers of arbitrary covariant derivatives of the curvature tensor. A classical solution, such as an Einstein metric, is called {\it universal} if, when evaluated on that Einstein metric, $T_{μν}$ is a multiple of the metric. A Ricci flat classical solution is called {\it strongly universal} if, when evaluated on that Ricci flat metric, $T_{μν}$ vanishes. It is well known that pp-waves in four spacetime dimensions are strongly universal. We focus attention on a natural generalisation; Einstein metrics with holonomy ${\rm Sim} (n-2)$ in which all scalar invariants are zero or constant. In four dimensions we demonstrate that the generalised Ghanam-Thompson metric is weakly universal and that the Goldberg-Kerr metric is strongly universal; indeed, we show that universality extends to all 4-dimensional ${\rm Sim}(2)$ Einstein metrics. We also discuss generalizations to higher dimensions.

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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