Conformal and Einstein gravity from twistor actions
Conformal and Einstein gravity from twistor actions
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DOI：
10.1088/0264-9381/31/4/045014
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发表时间：
2013-07
影响因子：
3.5
通讯作者：
T. Adamo;L. Mason
中科院分区：
文献类型：
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作者：
T. Adamo;L. Mason
我们将具有宇宙学常数的爱因斯坦引力嵌入到共形引力中，作为利用共形引力的扭转作用量的基础，不仅获得了共形引力的最大螺旋度破坏(MHV)散射幅度，而且还获得了具有非零宇宙常数背景下的爱因斯坦引力的最大螺旋度破坏(MHV)散射幅度。利用矩阵树定理对Feynman图求和，得到了引力MHV振幅与宇宙常数的新公式。我们证明了该公式是定义明确的(即，与某些规范的选择无关)，并且它非平凡地重现了平坦空间极限下的霍奇斯公式。我们初步讨论了由轴规中的共形引力扭转作用得到的更一般振幅的MHV形式。我们还看到，将爱因斯坦数据嵌入到共形引力作用中，可以在扭曲空间中进行脱离壳层的操作，从而给出一个自动产生相同MHV振幅的爱因斯坦扭曲作用的建议。这些概念自然延伸到N=4？>；超对称性。
We use the embedding of Einstein gravity with cosmological constant into conformal gravity as a basis for using the twistor action for conformal gravity to obtain maximal-helicity-violating (MHV) scattering amplitudes not just for conformal gravity, but also for Einstein gravity on backgrounds with non-zero cosmological constant. The new formulae for the gravitational MHV amplitude with cosmological constant arise by summing Feynman diagrams using the matrix-tree theorem. We show that this formula is well-defined (i.e., is independent of certain gauge choices) and that it non-trivially reproduces Hodges’ formula for the MHV amplitude in the flat-space limit. We give a preliminary discussion of an MHV formalism for more general amplitudes obtained from the conformal gravity twistor action in an axial gauge. We also see that the embedding of Einstein data into the conformal gravity action can be performed off-shell in twistor space to give a proposal for an Einsten twistor action that automatically gives the same MHV amplitude. These ideas extend naturally to N=4?> supersymmetry.