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arXiv 2404.03069hep-thmath-phmath.MP
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从坐标空间方程到Picard-Fuchs方程及返回

From equations in coordinate space to Picard-Fuchs and back

V. Mishnyakov, A. Morozov, M. Reva, P. Suprun

AI总结:

本文发展了Feynman多圈积分的坐标空间方法,以香蕉图为例,发现坐标空间算子的傅里叶变换包含动量空间的Picard-Fuchs算子作为最右因子,且将Picard-Fuchs算子转回坐标空间后结果再次因式分解。

摘要:

我们继续发展用于Feynman多圈积分方程的坐标空间方法。该方法的核心思想是,坐标空间中未积分的Greens函数乘积在动量空间中仍然是圈积分。自然的起点是著名的香蕉图,我们在本文中对此进行了探索。在坐标空间中,这些仅仅是 $n$ 个传播子的乘积。首先,我们解释这些函数满足一个 $2^n$ 阶方程。这些应与为动量空间积分推导的Picard-Fuchs方程进行比较。我们发现,坐标空间算子的傅里叶变换包含Picard-Fuchs算子作为最右边的因子。这些算子的阶数是一个特殊问题,特别是因为动量空间中的阶数由坐标空间中 $x$ 的次数决定。对于一般质量情况,这种因式分解模式很复杂,似乎傅里叶变换后的坐标空间算子的阶数远大于Picard-Fuchs的阶数。此外,人们可能会问,如果在因式分解之后我们将Picard-Fuchs算子带回坐标空间会发生什么。我们发现结果再次因式分解,最右边的因子是原始的坐标空间方程。我们通过示例演示了这是如何工作的,并讨论了对更复杂的Feynman积分的影响。

英文摘要:

We continue the development of a position space approach to equations for Feynman multi-loop integrals. The key idea of the approach is that unintegrated products of Greens functions in position space are still loop integral in momentum space. The natural place to start are the famous banana diagrams, which we explore in this paper. In position space, these are just products of $n$ propagators. Firstly, we explain that these functions satisfy an equation of order $2^n$. These should be compared with Picard-Fuchs equations derived for the momentum space integral. We find that the Fourier transform of the position space operator contains the Picard-Fuchs one as a rightmost factor. The order of these operators is a special issue, especially since the order in momentum space is governed by degree in $x$ in position space. For the generic mass case this factorization pattern is complicated and it seems like the order of the Fourier transformed position space operators is much bigger than that of the Picard-Fuchs. Furthermore, one may ask what happens if after factorization we take the Picard-Fuchs operators back into position space. We discover that the result is again factorized, with the rightmost factor being the original position space equation. We demonstrate how this works in examples and discuss implications for more sophisticated Feynman integrals.

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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