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arXiv 2501.07136hep-thgr-qc
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论零无穷远处引力在壳边界作用量的对称性

On symmetries of gravitational on-shell boundary action at null infinity

Shivam Upadhyay

AI总结:

本文利用程函五点振幅约束固定零无穷远引力边界作用量的角点歧义,并通过推广Geroch张量揭示超旋转、软引力子定理与无穷树图对称性的联系。

摘要:

我们重新考察渐近平直时空在零无穷远处的引力边界作用量。我们利用如下约束固定边界作用量中的角点歧义:在一般超平移真空中,在壳作用量(的指数)在程函近似下给出树图五点振幅。当BMS群被扩展以包含超旋转时,次领头软引力子定理自然地由在壳作用量导出。通过“推广”Geroch张量以纳入球面上的一组无散对称无迹张量,我们提出了无穷高的Goldstone模塔。这一推广在树图S矩阵中产生sub^n-领头软插入,从而为在该框架内理解无穷多树图对称性铺平道路。

英文摘要:

We revisit the gravitational boundary action at null infinity of asymptotically flat spacetimes. We fix the corner ambiguities in the boundary action by using the constraint that (exponential of) the on-shell action leads to tree-level 5-point amplitude in eikonal approximation in a generic supertranslated vacuum. The subleading soft graviton theorem follows naturally from the on-shell action when the BMS group is extended to include superrotations. An infinite tower of Goldstone modes is proposed by `generalizing' the Geroch tensor to incorporate a set of divergence-free symmetric traceless tensors on the sphere. This generalization leads to $\text{sub}^{n}$-leading soft insertions in the tree-level $\mathcal{S}$ matrix, thus paving the way to understanding the infinite tower of tree-level symmetries within this framework.

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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