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For the calculation of multi-loop Feynman integrals, a novel numerical method, the Direct Computation Method (DCM) is developed. It is a combination of a numerical integration and a series extrapolation. In principle, DCM can handle…

High Energy Physics - Phenomenology · Physics 2012-01-31 K. Kato , E. de Doncker , N. Hamaguchi , T. Ishikawa , T. Koike , Y. Kurihara , Y. Shimizu , F. Yuasa

We introduce a new framework for perturbatively computing equilibrium thermodynamic properties of cosmological phase transitions to high loop orders, using the full four-dimensional resummed thermal effective potential and avoiding the…

High Energy Physics - Phenomenology · Physics 2025-07-10 Pablo Navarrete , Risto Paatelainen , Kaapo Seppänen , Tuomas V. I. Tenkanen

We discuss an algorithm for the numerical evaluation of NLO multiparton processes. We focus hereby on the virtual part of the NLO calculation, i.e. on evaluating the one-loop integration numerically. We employ and extend the ideas of the…

High Energy Physics - Phenomenology · Physics 2012-09-14 S. Becker , D. Goetz , C. Reuschle , C. Schwan , S. Weinzierl

We describe three algorithms for computer-aided symbolic multi-loop calculations that facilitated some recent novel results. First, we discuss an algorithm to derive the canonical form of an arbitrary Feynman integral in order to facilitate…

High Energy Physics - Phenomenology · Physics 2015-06-03 Alexey Pak

Using loop-tree duality, we relate a renormalised $n$-point $l$-loop amplitude in a quantum field theory to a phase-space integral of a regularised $l$-fold forward limit of a UV-subtracted $(n+2l)$-point tree-amplitude-like object. We show…

High Energy Physics - Phenomenology · Physics 2020-07-01 Robert Runkel , Zoltán Szőr , Juan Pablo Vesga , Stefan Weinzierl

We extend the hidden zeros and $2$-split of tree-level ${\rm Tr}(\phi^3)$ amplitudes to loop-level Feynman integrands, apart from some physically irrelevant scaleless integrals. Our method is based on a certain factorization mechanism that…

High Energy Physics - Theory · Physics 2026-04-16 Kang Zhou

This work investigates in detail the performance and advantages of a new quantum Monte Carlo integrator, dubbed Quantum Fourier Iterative Amplitude Estimation (QFIAE), to numerically evaluate for the first time loop Feynman integrals in a…

High Energy Physics - Phenomenology · Physics 2024-11-20 Jorge J. Martínez de Lejarza , Leandro Cieri , Michele Grossi , Sofia Vallecorsa , Germán Rodrigo

In modern quantum field theory, one of the most important tasks is the calculation of loop integrals. Loop integrals appear when evaluating the Feynman diagrams with one or more loops by integrating over the internal momenta. Even though…

High Energy Physics - Theory · Physics 2020-06-24 Maxim Bezuglov

Finite Feynman integrals have been advocated as the optimal components for constructing a basis of master integrals in multiloop calculations, due to their improved analytic and numerical properties. In this paper, we show how the Loop-Tree…

The Loop-Tree Duality (LTD) theorem is an innovative technique to deal with multi-loop scattering amplitudes, leading to integrand-level representations over an Euclidean space. In this article, we review the last developments concerning…

Path integral Monte Carlo (PIMC) simulations have become an important tool for the investigation of the statistical mechanics of quantum systems. I discuss some of the history of applying the Monte Carlo method to non-relativistic quantum…

History and Philosophy of Physics · Physics 2016-11-23 Tilman Sauer

We study a neural network framework for the numerical evaluation of Feynman loop integrals that are fundamental building blocks for perturbative computations of physical observables in gauge and gravity theories. We show that such a machine…

High Energy Physics - Theory · Physics 2023-12-12 Ryusuke Jinno , Gregor Kälin , Zhengwen Liu , Henrique Rubira

In a recent paper we have presented an automated subtraction method for divergent multi-loop/leg integrals in dimensional regularisation which allows for their numerical evaluation, and applied it to diagrams with massless internal lines.…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. Binoth , G. Heinrich

Modern particle physics is increasingly becoming a precision science that relies on advanced theoretical predictions for the analysis and interpretation of experimental results. The planned physics program at the LHC and future colliders…

High Energy Physics - Phenomenology · Physics 2023-01-04 Ievgen Dubovyk , Ayres Freitas , Janusz Gluza , Krzysztof Grzanka , Martijn Hidding , Johann Usovitsch

The Feynman Path Integral is extended in order to capture all solutions of a quantum field theory. This is done via a choice of appropriate integration cycles, parametrized by M in SL(2,C), i.e., the space of allowed integration cycles is…

High Energy Physics - Theory · Physics 2015-03-13 D. D. Ferrante , G. S. Guralnik , Z. Guralnik , C. Pehlevan

We present an interesting study of Feynman integral reduction that does not employ integration-by-parts identities. Our approach proceeds by studying the equivalence relations of integral contours in the Feynman parameterization. We find…

High Energy Physics - Theory · Physics 2026-04-30 Ziwen Wang , Li Lin Yang

In the calculation of cross sections for infrared-safe observables in high energy collisions at next-to-leading order, one approach is to perform all of the integrations, including the virtual loop integration numerically. One would use a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Zoltan Nagy , Davison E. Soper

We present a new method for the numerical evaluation of arbitrary loop integrals in dimensional regularization. We first derive Mellin-Barnes integral representations and apply an algorithmic technique, based on the Cauchy theorem, to…

High Energy Physics - Phenomenology · Physics 2009-11-11 Charalampos Anastasiou , Alejandro Daleo

We consider Feynman integrals with algebraic leading singularities and total differentials in $\epsilon\,\mathrm{d}\ln$ form. We show for the first time that it is possible to evaluate integrals with singularities involving unrationalizable…

High Energy Physics - Theory · Physics 2020-08-18 Matthias Heller , Andreas von Manteuffel , Robert M. Schabinger

In this review, we discuss recent developments concerning efficient calculations of multi-loop multi-leg scattering amplitudes. Inspired by the remarkable properties of the Loop-Tree Duality (LTD), we explain how to reconstruct an integrand…

High Energy Physics - Phenomenology · Physics 2021-09-30 German F. R. Sborlini