Landau diagrams in AdS and S-matrices from conformal correlators
Landau diagrams in AdS and S-matrices from conformal correlators
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来自共形相关器的 AdS 和 S 矩阵中的朗道图
DOI：
10.1007/jhep11(2020)046
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发表时间：
2020
影响因子：
5.4
通讯作者：
Xiang Zhao
中科院分区：
文献类型：
--
作者：
S. Komatsu;M. Paulos;Balt C. van Rees;Xiang Zhao
AdS中的量子场论在边界上生成共形关联函数，并且在AdS几乎平坦的极限中，人们应该能够从这样的关联器中提取S-矩阵。我们讨论一个特别简单的位置空间过程来做到这一点。它的特点是从边界位置到（壳层上）动量的直接映射，从而将交比与Mandelivery不变量联系起来。这个配方在几个例子中是成功的，包括动量守恒的δ函数，并且可以被证明是基于梅林空间和OPE数据的[1]中的两个建议。有趣的是，这个过程并不总是有效的：费曼图的朗道奇点被证明是更大区域的一部分，被称为“坏区域”，维滕图的平坦空间极限在这里发散。为了捕捉这些分歧，我们介绍的概念，朗道图AdS。在平坦空间中，这些描述了在复杂空间中长距离传播的壳粒子，在每个体顶点都保持动量守恒。作为一个应用，我们恢复了四点三角图在坏区域边界处的异常阈值。
Quantum field theories in AdS generate conformal correlation functions on the boundary, and in the limit where AdS is nearly flat one should be able to extract an S-matrix from such correlators. We discuss a particularly simple position-space procedure to do so. It features a direct map from boundary positions to (on-shell) momenta and thereby relates cross ratios to Mandelstam invariants. This recipe succeeds in several examples, includes the momentum-conserving delta functions, and can be shown to imply the two proposals in [1] based on Mellin space and on the OPE data. Interestingly the procedure does not always work: the Landau singularities of a Feynman diagram are shown to be part of larger regions, to be called ‘bad regions’, where the flat-space limit of the Witten diagram diverges. To capture these divergences we introduce the notion of Landau diagrams in AdS. As in flat space, these describe on-shell particles propagating over large distances in a complexified space, with a form of momentum conservation holding at each bulk vertex. As an application we recover the anomalous threshold of the four-point triangle diagram at the boundary of a bad region.
影响因子：
5.4
作者：
S. Giombi;H. Khanchandani
通讯作者：
S. Giombi;H. Khanchandani
反德西特空间的限制
影响因子：
5.4
作者：
Aharony O
通讯作者：
Aharony O