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Related papers: Direct numerical integration for multi-loop integr…

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We present GW calculations of molecules, ordered and disordered solids and interfaces, which employ an efficient contour deformation technique for frequency integration, and do not require the explicit evaluation of virtual electronic…

Materials Science · Physics 2015-01-14 Marco Govoni , Giulia Galli

We present the computation of a full set of planar five-point two-loop master integrals with one external mass. These integrals are an important ingredient for two-loop scattering amplitudes for two-jet-associated W-boson production at…

High Energy Physics - Phenomenology · Physics 2020-12-30 S. Abreu , H. Ita , F. Moriello , B. Page , W. Tschernow , M. Zeng

We present an efficient algorithm for calculating multiloop Feynman integrals perturbatively.

Quantum Physics · Physics 2009-10-31 Boris Kastening , Hagen Kleinert

In this paper we present a treatment of hypersingular integral equations, which have relevant applications in many problems of wave dynamics, elasticity and fluid mechanics with mixed boundary conditions. The main goal of the present work…

Mathematical Physics · Physics 2007-05-23 G. Iovane , I. K. Lifanov , M. A. Sumbatyan

Canonical Feynman integrals are of great interest in the study of scattering amplitudes at the multi-loop level. We propose to construct $d\log$-form integrals of the hypergeometric type, treat them as a representation of Feynman integrals,…

High Energy Physics - Theory · Physics 2021-02-03 Jiaqi Chen , Xuhang Jiang , Xiaofeng Xu , Li Lin Yang

We present a simple method which simplifies the evaluation of the on-shell multiple box diagrams reducing them to triangle type ones. For the $L$-loop diagram one gets the expression in terms of Feynman parameters with $2L$-fold…

High Energy Physics - Theory · Physics 2015-06-18 D. I. Kazakov

We present a novel method to perform numerical integration over curved polyhedra enclosed by high-order parametric surfaces. Such a polyhedron is first decomposed into a set of triangular and/or rectangular pyramids, whose certain faces…

Numerical Analysis · Mathematics 2022-05-11 Pablo Antolin , Xiaodong Wei , Annalisa Buffa

We reformulate differential equations (DEs) for Feynman integrals to avoid doubled propagators in intermediate steps. External momentum derivatives are dressed with loop momentum derivatives to form tangent vectors to unitarity cut…

High Energy Physics - Theory · Physics 2017-06-26 Mao Zeng

We review the method of the calculation of multiloop integrals recently suggested in Ref.[Lee2010]. A simple method of derivation of the dimensional recurrence relation suitable for automatization is given. Some new analytic results are…

High Energy Physics - Phenomenology · Physics 2010-12-13 R. N. Lee

We present a new program package for calculating one-loop Feynman integrals, based on a new method avoiding Feynman parametrization and the contraction due to Passarino and Veltman. The package is calculating one-, two- and three-point…

High Energy Physics - Phenomenology · Physics 2007-05-23 Lars Brucher , Johannes Franzkowski

A new integration technique for multi-loop Feynman integrals, called the matrix method, is developed and then applied to the divergent part of the overlapping two-loop quark self-energy function $\,i\Sigma\,$ in the light- cone gauge. It is…

High Energy Physics - Theory · Physics 2009-10-28 George Leibbrandt , Jimmy Williams

We present a completely numerical method of calculating one-loop amplitudes. Our approach is built upon two different existing methods: the contour deformation and the extrapolation methods. Taking the best features of each of them, we…

High Energy Physics - Phenomenology · Physics 2017-02-01 Goran Duplancic , Bruno Klajn

In this paper we consider multi-loop integrals appearing in MHV scattering amplitudes of planar N=4 SYM. Through particular differential operators which reduce the loop order by one, we present explicit equations for the two-loop…

High Energy Physics - Theory · Physics 2015-06-04 L. Ferro

We present a new program package for calculating one-loop Feynman integrals, based on a new method avoiding Feynman parametrization and the contraction due to Passarino and Veltman. The package is calculating one-, two- and three-point…

High Energy Physics - Phenomenology · Physics 2011-04-20 L. Brücher , J. Franzkowski , D. Kreimer

This article is the third and last of a series presenting an alternative method to compute the one-loop scalar integrals. It extends the results of first two articles to the infrared divergent case. This novel method enjoys a couple of…

High Energy Physics - Phenomenology · Physics 2020-02-26 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

A systematic study of the scalar one-loop two-, three-, and four-point Feynman integrals is performed. We consider all cases of mass assignment and external invariants and derive closed expressions in arbitrary space-time dimension in terms…

High Energy Physics - Phenomenology · Physics 2016-04-14 Johannes Bluemlein , Khiem Hong Phan , Tord Riemann

The numerical unitarity approach has been important for obtaining reliable QCD predictions for the LHC. Here I discuss the extension of the approach beyond the leading quantum corrections for computing multi-loop amplitudes. The numerical…

High Energy Physics - Phenomenology · Physics 2017-03-27 Harald Ita

A new approach to compute Feynman Integrals is presented. It relies on an integral representation of a given Feynman Integral in terms of simpler ones. Using this approach, we present, for the first time, results for a certain family of…

High Energy Physics - Phenomenology · Physics 2020-03-18 Costas G. Papadopoulos , Christopher Wever

We introduce the concept of directed loops in stochastic series expansion and path integral quantum Monte Carlo methods. Using the detailed balance rules for directed loops, we show that it is possible to smoothly connect generally…

Strongly Correlated Electrons · Physics 2009-11-07 Olav F. Syljuasen , Anders W. Sandvik

We have presented some practical consequences on the molecular-dynamics simulations arising from the numerical algorithm published recently in paper Int. J. Mod. Phys. C 16, 413 (2005). The algorithm is not a finite-difference method and…

Exactly Solvable and Integrable Systems · Physics 2015-06-26 B. Brzostowski , M. R. Dudek , B. Grabiec , T. Nadzieja