ftint: Calculating gradient-flow integrals with pySecDec

The program ftint is introduced which numerically evaluates dimensionally regularized integrals as they occur in the perturbative approach to the gradient-flow formalism in quantum field theory. It relies on sector decomposition in order to determine the coefficients of the individual orders in ϵ = (4 - D)/2, where D is the space-time dimension. For that purpose, it implements an interface to the public library pySecDec. The current version works for massive and massless integrals up to three-loop level with vanishing external momenta, but the underlying method is extendable to more general cases.本文介绍了程序ftint，可数值计算量子场论（quantum field theory）中梯度流形式主义（gradient-flow formalism）微扰方法下出现的维数正则化积分（dimensionally regularized integrals）。该程序采用扇区分解（sector decomposition）方法，以确定ε=(4-D)/2展开式中的各阶系数，其中D为时空维度。为此，该程序实现了对公开库pySecDec的调用接口。当前版本支持三圈阶及以下、外部动量为零的有质量与无质量积分的计算，但其底层方法可扩展至更一般的应用场景。